Add a test API to query audio HAL version.

Add a test API to query audio HAL version. The HAL version is useful
for test since the HAL version cannot be determined from the platform
version. There can be some test requiring external devices connection
that can only run in CTS verifier but not the VTS. With a different HAL
version, there can be different CDD requirements for a given API. In
that case, the test will need to know the HAL version to behave
differently.

Bug: 195401076
Test: atest AudioManagerTest
Change-Id: I18cbf2f181e799e56b48916aefaede50389051fe