* perf(sqllab): Rendering perf improvement using immutable state
- keep queryEditors immutable during active state
- add unsavedQueryEditor to store all active changes
- refactor each component to subscribe the related unsaved editor state only
* revert ISaveableDatasource type cast
* missing trigger prop
* a default of an empty object and optional operator
* feat(explore): SQL popover in datasource panel
* Fix acequire not defined
* Rebase and fix tests
* Disable highlighting gutter
* Use ace-build acequire instead of brace
