facets: New parameter, RECORDS_REST_FACETS_FILTER, to filter the face…

[psaiz]

…ts based on a category based on all the other categories

:heart: Thank you for your contribution!

Description

This is inspired by the work of @ParthS007 here

The idea is to offer the possibility to apply the filters to the aggregations. As an example:

• Imagine a search with two different categories, cat1 and cat2.
• The user selects cat1=value1
• The current options are that either that selection is applied to the results, and the aggregation (standard filter), or only to the results (post_filter).
• This PR introduces a new option, where the filter is applied to the results, and to all the other aggregations (in the example, the aggregation of cat2 will return only the entrie that satisfy cat1=value1, but the aggregation for cat1 returns everything.

[ntarocco]

Tests are failing: it might be that you first want to have the changes validated?