Enable HID Device Profile Service (1/2)

* Enable the HID device profile service. The service is implemented in
the native Bluetooth stack.

* Change the behavior of HidDevService.onUnbind(). It also unregisters
the app.

Bug: 63384609
Test: Build. Test with SL4A.

Change-Id: I185d52bcf3f74a9abfc9ed28259a0495c5f0f56e