Server:
- ListOfSpeakers (LOS) is now a speprate model, containing of an id,
speakers, closed and a content_object.
- Moved all speaker related views from ItemViewSet to the new
ListOfSpeakersViewSet.
- Make Mixins for content objects of items and lists of speakers.
- Migrations: Move the lists of speakers from items to the LOS model.
Client:
- Removed the speaker repo and moved functionality to the new
ListOfSpeakersRepositoryService.
- Splitted base classes for agenda item content objects to items and
LOS.
- CurrentAgendaItemService -> CurrentListOfSpeakersSerivce
- Cleaned up the list of speakers component.
The old hidden type was used as internal, so everything is changed to
not be shown if the item is internal. hidden is "new", and actually
behaves as hidden now.
