Provide Ability to control overlays via BLE

[lsmith77]

Is your feature request related to a problem or use case? Please describe.
GoPro Labs support adding overlays via QR codes but this is not practical when the overlay should change during the recording, since it requires putting the QR code in front of the camera.

Describe the solution you'd like
With bluetooth support for controlling GoPro camera overlays this issue could be circumvented. This would make it possible to for example build an app that adds a real-time scoreboard overlay capabilities via bluetooth.

Describe alternatives you've considered
Ability to inject overlays in realtime via the Quick app for live streaming.

Additional context
gopro/labs#750