Merge changes from topic "audio-pre-v5"

* changes:
  Audio VTS: Simplify sequential #if
  Audio VTS: Fix missing whitespace in error message
  Audio HAL: Factorize Android.bp
  Audio HAL: Update file tree documentation
  Audio HAL: Factorize V2 and V4 like libaudiohal
  Audio VTS: Move version specific code to its own file
  Audio HAL: Align V2 and V4 VTS
  Audio HAL: Cleanup implementation
  Audio: Run clang-format on all files