Explore: POC for datasource query importers

Explore is about keeping context between datasources if possible. When
changing from metrics to logging, some of the filtering can be kept to
narrow down logging streams relevant to the metrics.

- adds `importQueries` function in language providers
- query import dependent on origin datasource
- implemented  prometheus-to-logging import: keeping label selectors
  that are common to both datasources
- added types

build: darwin compatible build env.

Fixes #13763 

fix for save dashboard redirect issue

fixed alert tab order and fixed some console logging issues

fix datasource testing

fix redirect issue, caused by timing of events between angular location change and redux state changes

Update google analytics code to submit full URL not just path

[skip ci]

Time regions support in graph panel

Explore: Don't suggest term items when text follows

[skip ci]

Team preferences support

filter out alpha plugins in plugins api 

elasticsearch: do not set a placeholder to index name, if it's already specified

[skip ci]

[skip ci]

[skip ci]