Replaced rems with pixels or variables (part 2)

Graphite: Fixed issue with using series ref and series by tag

Don't include non-existing image in MS Teams alert

Enable sass theme change in Storybook

show all numeric columns in singlestats/graph2

Small license correction

It seems the license should be applied little bit differently -
https://github.com/search?l=&o=desc&q=license%3Aapache-2.0&s=stars&type=Repositories.

Also see https://apache.org/licenses/LICENSE-2.0#apply

* grafana/master: (56 commits)
  another change that didn't come with earlier commit
  change that didn't come with in last commit
  reversed dashboard-padding
  Update CloudWatch metrics/dimension list (#16102)
  brought back dashboard-padding and panel-padding variables, made dashboard-padding more specific
  fix(prometheus): Change aligment of range queries (#16110)
  Minor refactoring of testdata query order PR #16122
  cleaner version
  maintain query order
  Update PLUGIN_DEV.md
  Merge with master, and updated logo and name
  more fixes to snapshot
  more fixes to snapshot
  removed empty space in snapshot
  fixed snapshot for test
  removed dashboard variables, removed headings-font-family variable, created theme variables for links and z-index, removed unused class in _panel_editor and _dashboard
  Tooltip: show percent instead of value
  Right tooltip position
  Add "No data points" message
  Improve tooltip look
  ...

Removed dashboard variables + minor things

update cloudWatch metrics/dimension list

- future alignment cause issues with rate charts and the display of last
values
- this change modifies the alignment to use the last available aligned
end date and no longer possibly requests data from the future

Update PLUGIN_DEV.md

Very alpha pie chart

* grafana/master:
  flot pairs

calculate flot pairs

If an image section is included in the JSON payload for MS Teams alerts
when no image URL exists, rendering of the alert in the client fails.
This change makes sure that an image section is only included in the
JSON payload if an image URL exists.

Closes #16082

Graphite: fixed nonNegativeDerivative argument hidden if 0

update TableData model