Audio route/Bluetooth and phone call interruption

Implemented Audio route change logic with the following priority - Bluetooth, headset and Speakers
Implemented Phone call interruption logic. Reset audio on interruption began and reverting back on interruption ended.
The call interruption logic works ok if you decline a call.
On accepting a call, the interruption end notification is called sometimes, sometimes a thread kill message is thrown by OT SDK. Have to work more on this
Also added a detectCurrent audio route utility methods
Added bunch of const strings for audio route change inputs.