Rewrite DebugInfoActivity to M3

[sunkup]

Purpose

Rewriting the DebugInfoActivity from M2 to M3, refactoring for more clarity, stability and test-ability at the same time.

Short description

As requested, I have not yet moved debug info generation into a data layer class. I have however added comments about this in the kdoc. Note, that I, however, moved the IntentBuilder to the ViewModel too, which should probably go to another helper/convenience class, since it's seemingly used throughout the whole app.

Enhancement

• Replaces M2 with M3 calls

Refactoring

• Extracts composables from activity to their own file as a dedicated compose "screen"
• Extracts view model from activity to its own file
• Switches from LiveData to compose mutableState and flows
• Introduces a private set (read-only) uiState in view model for the screen

Checklist

• [X] The PR has a proper title, description and label.
• [x] I have self-reviewed the PR.
• [x] I have added documentation to complex functions and functions that can be used by other modules.
• [x] I have added reasonable tests or consciously decided to not add tests.