Move AudioControl HAL to AIDL from HIDL

This is an initial pass at creating a AIDL AudioControl HAL
implementation for trout. This implementation does not add any
of the new features in the AIDL HAL, but simply passes through
the existing gRPC server messages to the new AIDL string
focus listener class via a mechanical conversion

Adding new ducking/muting features to the protocol and any
further cleanup will be done in subsequent CLs, but as-is this
commit allows trout to build cleanly again on the main branch

Bug: 175229146
Test: build trout
Change-Id: I090255fbc26a137413e0aa3db6b045ae76e76f9b