Introduce an inner "trampoline" class that implements
ISoundTriggerHw. This allows minor uprev implementation to inherit
from SoundTriggerHalImpl and reuse its functionality.
Split SoundModelClient into an abstract common part and
version-specific part. This allows the client to be redefined for
the types used in callback interface extensions.
Split the impl library into "core" part and the part implementing
HIDL_FETCH_ISoundTriggerHw function to avoid clash with the same
function introduced in minor uprev implementation.
Bug: 68823037
Change-Id: Ibec647f1aa7bc6a2a0bdfd1c9f9a066e4779a1bf
Test: make
