feat(bluetooth): add Bluetooth recording

[longregen]

Type of change(s)

• Bug fix
• Feature / enhancement
• Infrastructure / tooling (CI, build, deps, tests)
• Documentation

What changed and why

• A tab-like selector appears in the recorder fragment when a Bluetooth audio device is detected.
• I couldn't make the microphone start without also starting the "speaker" (outbound channel). I had to change a "w" for the file descriptor to "rw" because of that.
• Many little small changes related to testing and reducing log warnings about modern Android incompatibilities. Sorry for taking some liberties here! The debug&test cycle on-device (emulator doesn't have Bluetooth) was a little tedious.
• Moved isRunning = false into stopRecording() so it's consistently reset, properly clean files and fix a bug that caused always-on screen after recording stops.

Tests performed

• Open the app, without bluetooth enabled, functionality is the same, no changes.
• Open the app with bluetooth and a headset, a tab-like selector to allow bluetooth recording is whown
• Permission is only asked if needed.
• Device microphone works with no changes in functionality
• Bluetooth recording works, talked and walked away 10 meters away from the device and volume remains constant
• Bluetooth can't be tested on emulator. It took me quite a while to figure out how to make it work.

Before & after preview

Before, After, and in light mode

Closes the following issue(s)

• Closes Can not use Bluetooth headset microphone #54

Checklist

• I read the contribution guidelines.
• I manually tested my changes on device/emulator (if applicable).
• I updated the "Unreleased" section in CHANGELOG.md (if applicable).
• I have self-reviewed my pull request (no typos, formatting errors, etc.).
• I understand every change in this pull request.