Unify related - WIP
Unify related - WIP

Done:
- Move the show_filter to global
- Change the way max_items works
- Add lots of comments to _get_bhp_related to make it clearer
- Remove the exclusion of photo units from text search

ToDo:
- Add automatic index creation on "need exactly one text index for $text query"
exception

Beit-Hatfutsot/dbs-back,Beit-Hatfutsot/dbs-back,Beit-Hatfutsot/dbs-back,Beit-Hatfutsot/dbs-back