Datasource docs for Loki

cli: chmod 755 for backend plugin binaries

Fixes #15477

Fixes #15500. Does a simple filename check if the binary names ends
with _linux_amd64 or _darwin_amd64 then sets the file mode to 755.

Add Lux to units

Remove maxDataPoints and interval props from props to remember in panel model

Changed how react panels store their options

* Added a ReactPanelPlugin as the interface that react panels export, this way react panels have clearer api, and gives us hooks to handle migrations and a way for panel to handle panel changes in the future
* Moved gauge value options into a sub oject and made editor more generic, will be moved out of gauge pane later and shared between singlestat, gauge, bargauge, honecomb
* Also remove nested options prop that was there due to bug
* Added missing Gauge props
* Fixed gauge issue that will require migration later and also value options editor did not handle null decimals or 0 decimals
* Fixed unit tests
* More fixes for react panels

Removed primary class from Add Query button, and changed name of panel options tab

Fix typo in view mode cycle button

Removed primary class from Add Query button, and changed name of Panel Options tab o General Options

- adds Loki data source docs to Grafana docs
- moved query-related docs from Explore to Loki

Added enable_gzip documentation (#15322)

Fixed issue with PanelHeader and grid-drag-handle in fullscreen

fixes #15479

Fixed issue with PanelHeader and grid-drag-handle class still being applied in fullscreen, fixes #15480

Fixed prettier CI issue that caused build failures

Fixed handling of alert urls with true flags

Fix percent_diff calculation when points are nulls

Improved documentation of new short-lived token solution

Added missing strict type checking options to grafana/ui 

Fixed dashboard navbar buttons being visible in fullscreen

added support for influxdb non_negative_difference function in tsdb 

Move error boundry from DataPanel to PanelChrome

Support ANSI colors codes in Loki logs