Extract native methods and add unit tests for HID Device

* Isolated JNI native interface in a separate class
HidDeviceNativeInterface so that is can be mocked
when testing HidDeviceService
* Add singleton setter and getter for HidDeviceService
* Use BluetoothDevice object instead of address in HidDeviceService
* Add unit tests for HID Device service

Test: HID Device unit test passes; SL4A test passes
Bug: 69045106
Change-Id: I28cffe1fa1469199d98062b5b52b136697b4cb91