* Prometheus: Add metadata to metrics in Metrics browser
- use the available metadata to enhance the tooltip on metric items in the metrics browser
- added meta info for histogram metrics (was missing before)
- also added one for ALERTS
* fix test
* Loki/Prometheus: Improve label browser performance
- raise limits
- introduce debounce for Metrics browser filter fields (not done for Loki)
- discard facetting responses when selector was already changed again by user
* Clean up comments and imports
* [WIP] Metrics browser
* Removed unused import
* Metrics selection logic
* Remove redundant tests
All data is fetched now regardless to the current range so test for checking reloading the data on the range change are no longer relevant.
* Remove commented out code blocks
* Add issue number to todos
Co-authored-by: Piotr Jamróz <pm.jamroz@gmail.com>
