Make active device change asynchronous.
Restructure A2DP active device change API
for clarity and speed.
Merge active device and device config change
handlers.
Fix bug for a new A2DP device connection with
handleBluetoothA2dpActiveDeviceChange.
Bug: 122944517
Test: still needs Bt side using new interface
Change-Id: Ia2fa6b2c98ed4452880e8abca4a069b904f8cc68
d7c9598a26