Motion detail component refactoring

[bastianjoel]

In preparation for #3529 the motion components should be refactored.

Mainly the following things should be done:

1. Move create/edit form into its own component
2. Simplify control flow in templates
3. Change change detection strategy to OnPush if possible with minor changes
4. Replace repo calls with direct view model observable calls as of Fix list of speakers names not displayed #3993 if reasonable