Migrate legacy screens to Jetpack Compose

[mtotschnig]

This ticket is for gathering ideas on how screens built with the Android view system can be migrated to Jetpack Compose:

1. Transaction Edit Screen: The most complex, but in the long run probably the most rewarding because at least some part of the complex state handling would be made easier with Compose.
2. Tag Managment: Depends on https://github.com/google/flexbox-layout, which is not actively maintained (Is this repository currently being maintained? What are the future plans for this repo?  google/flexbox-layout#561), and has one bug that also hits us occasionally (RecyclerView crashing in some circumstances google/flexbox-layout#240) so migrating would have the benefit of reducing technical debt.