Merge branch 'data-source-instance-to-react' of https://github.com/grafana/grafana into data-source-instance-to-react

fix for influxdb annotation issue that caused text to be shown twice

New data source as separate page

docs: fix minor typos

Fix text overflow on playlist search  #13464

fix gofmt tests output

Fixed typo in query editor placeholder text.

Explore: resize graph on window resize

Print the whole command in "Execute ..." and "... returned 1" logs.
Fix "binary operator expected" by passing quoted output from
`gofmt` to `test`.

ux: misc react migration fixes and info box style improvement

Explore: reset typeahead on cursor move

Explore: fix rate hint for series with null values

Moving contributing.md to top level

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