Run queries for sql data sources for panels with multiple queries concurrently
Also make max open connections, max idle connections and max connection 
lifetime configurable in the data source settings

Explore: highlight typed text in suggestions

wip: whats new for 5.3

Plus a few tweaks to the text

Update mac.md

Update windows.md

Update rpm.md

[skip ci]

[skip ci]

cloudwatch: automatically set graph yaxis unit 

fixes #13575

This will stop a segfault from happening

Render Dashboard Row drag handle only in edit mode

fix CloudWatch id validation

Update debian.md

Stackdriver heatmap support. Fixes #13559

Improve Stackdriver provisioning docs

- use react-highlight-words
- add highlighting (color and border) to the matching substring of the
  suggested items in the typeahead
- extracted match finding from logging datasource
- created new utils/text.ts class for text-related functions
- added more types

Remove duplicate labels in the datasource query

ux: minor update to look of stackdriver query help

Explore: compact state URLs

Explore: trigger a query field render to fix highlighting