Implement discoverability and some bluetooth fixes: - Discoverability: make the system visible to other bluetooth devices - Trusted: when successfully paired and connected, mark device as Trusted so it can automatically connect again. - Connect the Audio interface for all audio devices, including Headsets. Some bluetooth audio devices that don't contain a microphone still show up as Headsets, and won't connect successfully otherwise. This will still work for standard headsets, since Audio connects all audio interfaces. - Stop discovery when a device is selected for connection, and it sometimes causes connection attempts to fail. Fixes: 1268047, 1331642