Backend: Merge master into the backend branch (#845)

* CI: fix shellcheck issues (#789)

Signed-off-by: Mario Trangoni <mjtrangoni@gmail.com>

* annotations: fix options in grafana 6.x, fix #813

* fix function editor in Grafana 6.4, closes #810

* add typings for grafana packages

* Add $__range_series variable for calculating function over the whole series, #531

* fix tests

* Don't set alert styles for react panels, fix #823

* docs: add range variables

* docs: percentile reference

* fix codespell

Co-authored-by: Mario Trangoni <mario@mariotrangoni.de>
Co-authored-by: Alexander Zobnin <alexanderzobnin@gmail.com>

src/test-setup/jest-setup.js

@@ -52,6 +52,7 @@ jest.mock('grafana/app/core/utils/datemath', () => {
 jest.mock('grafana/app/core/utils/kbn', () => {
   return {
     round_interval: n => n,
+    secondsToHms: n => n + 'ms'
   };
 }, {virtual: true});