App Lounge: Refactor Fragments and viewmodels

Summary

Some Fragments lifecycle methods contain lots of code. It's needed to divide them by extracting small methods in order to increase readability.

There are some duplicate ui methods in the fragment, We can move them to a utility class and access them from fragments.

Viewmodels contain business logic, it's needed to move them from ViewModel to repositories in order to increase maintainability and unit testing. There are some already done, we need to review and refactor more.