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.
