Define audio HAL

Created after hardware/audio.h with the following changes:

 - names changed to satisfy HAL style guide;

 - defined getter / setter methods for properties, and interfaces
   for devices where needed;

 - stream out callback changed to be used over RPC;

 - 'dump' method is already defined by BBinder, so in HAL
   interfaces it is replaced by 'debugDump'.

Note that audio data is currently transferred using byte buffer,
which is not effective due to memory copy and HwBinder transaction
involved. The transfer method will be changed to FastMessageQueue.

Bug: 30222631
Test: make

Change-Id: Ibb3bd940a91820e81d1a2b53b38d63b9e3de148a