Add an getViewModelListBehaviorSubject that simplifies
how to get most model lists in the view
unified update, delete and create methods and removed redundant code from the repos
(where it was possible)
cleaned up the motion detail to not directly use the DataStore
Add information about the "main model" to all ViewModels, to call the
correct constructor in the BaseRepo
Seperates the previously large motion module in various smaller
and very small feature modules.
Motion Detail, and all direct dependancies to Motion Detail
is now an own module.
This significantly increases the response time of openslides 3