audio: Refactor streams implementation

Simplify the experience of implementing stream variants.
Stream class now exposes two interfaces: DriverInterface
and StreamCommonInterface, which represent the two
aspects of its usage: via the FMQ on the worker thread,
and via IStreamCommon Binder interface.

Input/output streams now inherit the concrete stream
variant, and implement interface methods specific for
IStreamIn and IStreamOut.

Added DriverInterface::shutdown method which is called
on the worker thread prior to the exit.

Bug: 282568751
Test: atest VtsHalAudioCoreTargetTest
Change-Id: I5bf8da2f22b27f0e284a41fc30b920d87ac2936c