This changes the rate and increase queries to not calculate
a value when there is no previous value. This also adds an
order by metric column to prevent inconsistent series ordering
in the legend.

[skip ci]

Alert Teams - Adding Action to view the graph by its public URL.

[skip ci]

[skip ci]

[skip ci]

Add min time interval support for SQL datasources

make default values for alerting configurable

[skip ci]

[skip ci]

docs: default paths in the docker container.

upgrade to golang 1.11

* auth: never authenticate passwords shorter than 4 chars.

* auth: refactoring password length check.

* auth: does not authenticate when password is empty.

* auth: removes unneccesary change.