Explore: typeahead and render performance improvements

- remove `edited` property of query objects
- query object semantics changes to be initial values only
- resetting or externally modifying a query is done via giving it a new
  react key, which replaces the row completely
- query changes while typing are sent up to Explore to be saved in a
  local property that is not part of the component state (prevent
  control circle)
- all Explore functions using the queries must access the local property
  for current values

- Lower debounce
- refactor suggestion selection
- make Portal pure
- use prev suggestions object if suggestions are the same

move timeFrom, timeTo, unixEpochFrom and unixEpochTo macros to sql_engine

[skip ci]

Keep trailing slash for datasource proxy requests

Fix megacheck issues

centered dashboard icon in search with flexbox

stackdriver: adds missing nginject attribute

Fix issue with updating role permissions #13507

build: automatically publish releases to grafana.com.

See,
$ gometalinter --vendor --disable-all --enable=megacheck --disable=gotype --deadline 6m ./...
pkg/tsdb/postgres/postgres_test.go:120:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/postgres/postgres_test.go:200:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/postgres/postgres_test.go:257:34:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/postgres/postgres_test.go:282:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/postgres/postgres_test.go:336:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/postgres/postgres_test.go:363:32:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/postgres/postgres_test.go:453:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/postgres/postgres_test.go:475:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/postgres/postgres_test.go:497:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/postgres/postgres_test.go:519:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/postgres/postgres_test.go:541:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/postgres/postgres_test.go:563:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/postgres/postgres_test.go:585:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/postgres/postgres_test.go:607:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/postgres/postgres_test.go:629:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/postgres/postgres_test.go:652:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/postgres/postgres_test.go:677:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/postgres/postgres_test.go:738:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/postgres/postgres_test.go:761:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/postgres/postgres_test.go:787:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/postgres/postgres_test.go:817:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/postgres/postgres_test.go:847:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/postgres/postgres_test.go:877:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/postgres/postgres_test.go:905:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/postgres/postgres_test.go:933:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)

See,
$ gometalinter --vendor --disable-all --enable=megacheck --disable=gotype --deadline 6m ./...
pkg/tsdb/mysql/mysql_test.go:132:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/mysql/mysql_test.go:220:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/mysql/mysql_test.go:267:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/mysql/mysql_test.go:330:34:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/mysql/mysql_test.go:355:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/mysql/mysql_test.go:381:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/mysql/mysql_test.go:476:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/mysql/mysql_test.go:498:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/mysql/mysql_test.go:520:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/mysql/mysql_test.go:542:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/mysql/mysql_test.go:564:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/mysql/mysql_test.go:586:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/mysql/mysql_test.go:608:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/mysql/mysql_test.go:630:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/mysql/mysql_test.go:652:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/mysql/mysql_test.go:674:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/mysql/mysql_test.go:696:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/mysql/mysql_test.go:719:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/mysql/mysql_test.go:744:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/mysql/mysql_test.go:805:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/mysql/mysql_test.go:828:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/mysql/mysql_test.go:854:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/mysql/mysql_test.go:884:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/mysql/mysql_test.go:914:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/mysql/mysql_test.go:944:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/mysql/mysql_test.go:972:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/mysql/mysql_test.go:1000:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)

See,
$ gometalinter --vendor --disable-all --enable=megacheck --disable=gotype --deadline 6m ./...
pkg/tsdb/mssql/mssql_test.go:131:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/mssql/mssql_test.go:221:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/mssql/mssql_test.go:268:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/mssql/mssql_test.go:330:34:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/mssql/mssql_test.go:355:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/mssql/mssql_test.go:444:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/mssql/mssql_test.go:466:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/mssql/mssql_test.go:488:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/mssql/mssql_test.go:510:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/mssql/mssql_test.go:532:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/mssql/mssql_test.go:554:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/mssql/mssql_test.go:576:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/mssql/mssql_test.go:598:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/mssql/mssql_test.go:620:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/mssql/mssql_test.go:643:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/mssql/mssql_test.go:666:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/mssql/mssql_test.go:742:34:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/mssql/mssql_test.go:819:34:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/mssql/mssql_test.go:895:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/mssql/mssql_test.go:918:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/mssql/mssql_test.go:944:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/mssql/mssql_test.go:974:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/mssql/mssql_test.go:1004:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/mssql/mssql_test.go:1034:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/mssql/mssql_test.go:1062:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/mssql/mssql_test.go:1090:33:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)

See,
$ gometalinter --vendor --disable-all --enable=megacheck --disable=gotype --deadline 6m ./...
pkg/tsdb/elasticsearch/client/client_test.go:28:25:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/elasticsearch/client/client_test.go:39:25:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/elasticsearch/client/client_test.go:51:25:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/elasticsearch/client/client_test.go:63:25:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/elasticsearch/client/client_test.go:76:25:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/tsdb/elasticsearch/client/client_test.go:89:25:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)

See,
$ gometalinter --vendor --disable-all --enable=megacheck --disable=gotype --deadline 6m ./...
pkg/services/alerting/notifiers/telegram_test.go:55:44:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/services/alerting/notifiers/telegram_test.go:71:45:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/services/alerting/notifiers/telegram_test.go:88:45:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)
pkg/services/alerting/notifiers/telegram_test.go:104:45:warning: do not pass a nil Context, even if a function permits it; pass context.TODO if you are unsure about which Context to use (SA1012) (megacheck)