#7120 - Alter language facet to count unique documents regardless of culture

Redmine ticket: https://projects.artefactual.com/issues/7120

* Add 'Unique documents' count to languages facet: shows the number of documents that match the query regardless the language. When a language is selected it needs a second query without language filter to know the real count.
* Makes ES queries over all available cultures (except autocompletes)
* Change sort field and result values to the selected language facet
* Allows boost options when all culture fields are being set