[Doc] Add an UpdateRequest example to Java API doc

Closes #7083.
java: QueryBuilders cleanup: remove deprecated

Related to #8667:

Some QueryBuilders have been deprecated in 1.x branches. We removed them in 2.0.

Removed
-------

* `textPhrase(...)`
* `textPhrasePrefix(...)`
* `textPhrasePrefixQuery(...)`
* `filtered(...)`
* `inQuery(...)`
* `commonTerms(...)`
* `queryString(...)`
* `simpleQueryString(...)`

Closes #8721.
[TEST] remove action names bwc layer

The bwc layer added with #7105 is not needed in master as a full cluster restart will be required, thus from 2.0 on the only supported action names are compliant to the defined conventions and don't need to be converted to the old format

Closes #8758
[DOCS] Document ActionNamesTests
[Doc] Java API: add search templates

Closes #7321.