Limit options and add setting to editor

[Elblinator]

resolves #5418
settings from backend: motions_enable_restricted_editor_for_manager and motions_enable_restricted_editor_for_non_manager

[Elblinator]

I decided to the things in override ngAfterViewInit() bc we use extensions and not plugins
Extensions cannot be removes like plugins

[Elblinator]

Clear formatting was exempt from the if active because this is a function which can always be called and is not coupled with any extension

[bspekker]

Hopefully very small remark: Please move the two new settings to the end of the "View" section.