Make use of DomainsLayers/UseCases

[mahibi]

As the app grows and calls to repositories are needed in multiple places, it makes sense to make use of "UseCases" to avoid redundant code.

Explanation at https://medium.com/@ami0275/mvvm-clean-architecture-pattern-in-android-with-use-cases-eff7edc2ef76

As an example where this would make sense look at this comment: https://github.com/nextcloud/talk-android/pull/4333/files#r1810614023

As soon as a some UseCases have been implemented, this issue can be closed and the implementations should serve as a example.