Reduce trigger functions for equal fields

[hjanott]

To reduce them we have two approaches. Either combining them with parameter adjustment and logic changes or removing/altering such fields.
The latter can be done for:

• option/content_object_id : user/option_id (Here we would need to reference meeting_user instead and would get rid of two functions)
• projection/content_object_id : meeting/projection_ids (Here we would need to add an in-between model like welcome_card.)