Fixes#2492
* Added api/groups/{id} endpoint for retrieving a single group by its id
* Fixed GroupRepository incorrectly opening query to User instead of Group model
* Added filtering & paging abilities to GET api/groups endpoint
* Added test for sorting for GET api/groups endpoint
Co-authored-by: Alexander Skvortsov <38059171+askvortsov1@users.noreply.github.com>
* - Add ID to fields searched in group gambit
- Use joins instead of looping in group gambit
* Add visibility scoping to group gambit
* call IDs userIds
* If group identifier is numerical, treat it as an ID
