Add tslib to TS compiler

Karma to Jest: variable_srv_init

- using tslib reduces bundle sizes
- add compiler option for easier default imports of CJS modules
- remove double entry of fork-ts-checker-plugin
- speed up hot reload by using exprimental ts-loader API

Docs: Prometheus template query variables

Included example usages

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adjust table header contrast for the light theme

fix invalid reference

fix failing test due to time diff issues

Karma to Jest: graphite query_ctrl

Karma to Jest: completer

Karma to Jest: influx query_ctrl

docs: mentation that config changes requires restart.

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CloudWatch backend return 400 if user input error

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