BT: Multi A2dp support in Settings App.

1. The connected sinks are not disconnected from
A2dpProfile when new sink is connecting.
2. Also return correct connection status for
specific HS.
3. Sets priority for specific HS while disconnecting.

Change-Id: I56142d1527aa86d2bb47fb7166b2f3ab451d9b17

Bluetooth: Add support of two A2dp connections.

Audio Service will now manage two a2dp connections
and makes sure that BT a2dp connections are
consistently seen by other applications.
The change removes the BD address usage in BT
names, and uses a new Strin "BluetoothA2dp"
in order to show A2dp connected devices.

Change-Id: I59b8f8eff7bbc8033fcd46d0ac21d94ee338ca36

Purge A2dp connected device list

Purge A2dp connected device list on A2dp service connect incase the
same is not purged during service disconnect earlier.

Change-Id: Ie4e7e79530eaf2ec138bb5d0c51996d4172eb4b9

Update A2DP device connection state properly.

Update Audio devices only for first connected
and last disconnected A2DP devices.

Change-Id: I3ac83e507e2b8c638a08881cd70f7900c9312391