* Elasticsearch - Term aggregation limit fix  (should fix #7112)

* Elasticsearch - Term aggregation limit fix

Add a note about the `go get` warning that the user sees when following the setup instructions.

Added commonly used kilo-prefixed energy units

Kilovolt-ampere reactive (kvar)
Kilovolt (kV)
Kiloampere (kA)

Change all bool queries to use 'filter' clause instead of 'must' for
better performance

Documentation calls for `annotationQuery` but the [example](https://github.com/grafana/simple-json-datasource/blob/205cf4cfbce95cd455da97c7972b64538cc80ab3/src/datasource.js#L41) uses the method name `annotationQuery`

Use configuration variable "show_alerting_ui" to show/hide alerting UI

I noticed tooltips on other panels rendering outside of their panel or
even the browser window when hovering on the very edge of graphs with
relative time overrides.