* Grafana/Loki: Adds support for new Loki endpoints and metrics
* Adds `/loki/` prefix to new loki endpoints and updates response interfaces
* Improved legacy support
* Removed changes related to plugin.json and added Loki-specific hacks
* Fixes live streaming for legacy loki datasources
* Refactor: Removes replaceUrl from actions
* Refactor: Moves saveState thunk to epic
* Refactor: Moves thunks to epics
* Wip: removes resulttype and queries once
* Refactor: LiveTailing uses observer in query
* Refactor: Creates epics folder for epics and move back actioncreators
* Tests: Adds tests for epics and reducer
* Fix: Checks for undefined as well
* Refactor: Cleans up previous live tailing implementation
* Chore: merge with master
* Fix: Fixes url issuses and prom graph in Panels
* Refactor: Removes supportsStreaming and adds sockets to DataSourcePluginMeta instead
* Refactor: Changes the way we create TimeSeries
* Refactor: Renames sockets to streaming
* Refactor: Changes the way Explore does incremental updates
* Refactor: Removes unused method
* Refactor: Adds back Loading indication
* fix(explore): Prevent double querying for Prometheus and Loki
- queries were triggered twice because two Enter handlers existed
- removed runner plugin from Loki and Prom query fields (runner plugin
is still being used in azure)
Part of #16995
* Set loki's mtrics capability to false
Loki is not a metrics store. Explore was using the `metrics` field in
the plugin definition to issue a second query run. But Loki shows only
one result viewer.
Fixes#16995
