implement audio note taking

How to test

1. checkout the project
2. build a server, VR client
3. confirm the voice chat works (best way to do this is to run a desktop client and a VR client at the same time and listen)
4. in the VR app, press SecondaryButton (B on right or Y of left)
5. confirm there is a UI text element displayed and a slider with time elapsing
6. say something nice. You are recording a voice note for future you, I heard he's a cool guy. Confirm that you are muted.
7. press the button again
8. confirm that you are unmuted
9. follow the directions in VoiceRecordingManager.cs to access the recordings on your headset
10. confirm the note has been recorded

assigned to @422208

changed the description

requested review from @451448 and @251919

merged

mentioned in commit 9c2d0adf