wip: Fix playlists "by tags"

* do not mutate seriesList in mergeSeriesByTime

* extendedseriesList -> extendedDatapointsList

* remove toString() from datapoints, since the value can be null

Fixed right side scrollbar margin on dashboard page

Fixing bits valueFormat

Fix style and grammar in 6.0 announcement

prevent datasource json data stored as nil

closes #14239

run db tests in all packages

Return 404 on user not found

closes #10506

service: fix for disabled internal metrics.

Closes #15715

Explore: Enable click on name label

- click on the name label in a prometheus table was disabled
- it was disabled because every query used to have a metric which is no
longer true
- this change enables it

grafana/ui 6.0.1-alpha.0 release version bump

Need this to be available for plugins

Update of the internal metrics for Grafana was
disabled by mistake when refactoring the code.

Fixes #15651

docs: grafana 6.0 has been released.

moves tracing packge into /infra

moves social package to /login

ref #14679

graph: fixes click after scroll in series override menu

Fixed value dropdown not updating when it's current value updates

moves metric package to /infra

stackdriver: fix for float64 bounds for distribution metrics