api_views.py:
- remove 'id' from all filter_fields, django-filter doesn't allow filtering by primary key, and it doesn't really make sense to do so anyway
- added SubjectDetail view
- added SiteDetail view
- added PanelDetail view
- added ParameterDetail view
- added CompensationDetail view

serializers.py:
- add url hyperlink field to the rest of the Model serializers

urls.py:
- add api routes for the 5 new detail views