* Explore: facetting for label completion
- unified metric and non-metric label completion
- label keys and values are now fetched fresh for each valid selector
- complete selector means only values are suggested that are supported
by the selector
- properly implemented metric lookup for selectors (until the first
metric was used which breaks when multiple metrics are present)
- typeahead tests now need a valid selection to demark the cursor
* Fix facetting queries for empty selector
- classic dashboard panels inject a dynamic query interval as part of
the query options. Explore did not have that.
- this PR adds the interval calculation to Explore
- interval based on Explore container's width
- ensure min interval if set in datasource
* time selector for explore section
* mostly ported the angular time selector, but left out the timepicker
(3rd-party angular component)
* can be initialised via url parameters (jump from panels to explore)
* refreshing not implemented for now
* moved the forward/backward nav buttons around the time selector
* adds +/- buttons to query rows in the Explore section
* on Run Query all query expressions are submitted
* `generateQueryKey` and `ensureQueries` are helpers to ensure each
query field has a unique key for react.
