Implement everything as a watchapp

[mortenfyhn]

This is the ultimate goal of this project: Get support into PebbleOS for application level BLE controls, so we can implement the whole MiniMed interface as a watchapp that anyone can run on stock PebbleOS.

Then probably this repo can be archived, and work continue in a new watchapp repo.

Step one:

• Application-Level Generic BLE GATT Client + Background Execution coredevices/PebbleOS#853

I believe Eric of Core Devices has expressed interest in merging this if someone implements it.