Stackdriver: Support meta labels (#21373)

* Rewrite angular segments for filter and group by in react

* wip: refactoring

* Update metric find queries

* Remove old maps used to create labels - use one map for all types instead

* Use value as label (again) for filters ang groupby

* Remove old filter

* Remove not used code

* Fixes after pr feedback

* Fix broken tests and add new metadata tests

* Add index file to make imports cleaner

* Cleanup. Remove old angular filter code

* Fix broken tests

* Use type switching instead of if statements

* Use globals for regex

* Updates after pr feedback

* Make sure it's possible to filter using the same key multiple times

* Replace metric select with segment component

* Pass template vars as props

* Refactor meta labels code

* Reorder template variables

* Fix broken tests

* Reset metric value when changing service

* Fix lint issue.

* Make tests independant of element order

* Include kubernetes.io in regex

* Add instruction in help section

public/app/plugins/datasource/stackdriver/components/SimpleSelect.tsx

@@ -7,7 +7,7 @@ interface Props {
   label: string;
 }
 
-const SimpleSelect: FC<Props> = props => {
+export const SimpleSelect: FC<Props> = props => {
   const { label, onValueChange, value, options } = props;
   return (
     <div className="gf-form max-width-21">
@@ -24,5 +24,3 @@ const SimpleSelect: FC<Props> = props => {
     </div>
   );
 };
-
-export default SimpleSelect;