Bluetooth: Add Get/Set socket option to the Bluetooth Socket

Introduced Get/Set socket option to the Bluetooth Socket.
For these APIs it will directly call the APIs of Adapter
Service.The corresponding APIs have been implemented in
the Adapter service of native Bluetooth APK.

Change-Id: Ic49b66599fb3c4c500e52295895d708dbc172cc7
Bluetooth: DUN: Add framework changes to support DUN

Bluetooth DUN profile APIs added to the framework APIs.
As DUN server supports only disconnection of DUN profile
level connection this API is implemeted along with other
APIs.

It registers bluetooth state changed callback with the
adapter service,once there is a change in the bluetooth
state,it will bind/unbind the DUN service which is
implemented in BluetoothExt.APK.

DUN service, and other DUN Application layer are mplemented
in BluetoothExt.APK.

Change-Id: I6ce1204ac6138e28ad7486f2855f0f7444ad3886