Docs for mssql for #11642

Docs variable interpolation

Was missing a tilde in the tag_values example

docs: What's new in v5.1 

* master:
  build: only lint the pkg folder
  changelog: adds note about closing #11476
  singlestat: Fix optimization in setTableColumnToSensibleDefault
  influxdb: Check before assuming first column to be 'time'

add's info about new template variable interpolation

Improved scrolling experience

reduce content a little bit and highlight mssql and prom heatmap

influxdb: Check before assuming first column to be 'time'

Add gometalinter to CircleCI

remove unused variables detected by varcheck

csv option in postgres/mysql docs and the regex option in the
graphite docs

ref #11388 and ref #9911 and ref #10366

Fixes #11388
Ref #11141

[skip ci]

add tabs and search filter to new panel control

External auth refactor