* changed var to const

* fixed typo created in last commit

* added or empty object to options in prometheus/datasource

Update provisioning.md

* added empty cta to playlist page + hid playlist table when empty

* implemented the empty-list-cta component

* removed extra protip, changed messaging

wrong data type was mentioned in table for esVersion field. I expect to regenerate doc here: http://docs.grafana.org/administration/provisioning/#datasources
This problem was noted by @stefanes a while ago here: https://github.com/grafana/grafana/issues/11126#issuecomment-370799209

docs: How to get started with Grafana for the first time

[skip ci]

animation during slow login

* Interface linting rule

* fix: changed model names in store files so that the interface names do not conflict with the model names

[skip ci]

Replacing variable interpolation in "All value" value

Closes #12980

[skip ci]

Heatmap: fix tooltip and crosshair in firefox

tests: fix missing tests (with .jest suffix)

Update notifications.md

[skip ci]

Fix: Template variables are executing excessive queries

Explore: Fix label filtering for rate queries

Explore: still show rate hint if query is complex

Explore: Filter out existing labels in label suggestions