PBAP: Use ACTION_CONNECTION_STATE_CHANGED intent

* Use ACTION_CONNECTION_STATE_CHANGED to broadcast connection state
  change to comply with BluetoothProfile interface requirement
* Use BluetoothProfile.STATE_* variables to represent connection
  states for PBAP profile
* Receive this intent in AdapterProperties to track PBAP state change
  in profile state reference counter

Bug: 63873163
Test: Connect to car kits
Change-Id: Ie0eb775ae7f7a55cd0c2ad96858feec18b73ab6f