Define VehicleHalInterfaceDefaults to wrap VHAL backend.

This allows prevents libraries from directly depending on a specific
version of AIDL VHAL interface, which allows an easier update for
VHAL interface version.

Test: Local build.
Bug: 235152525
Change-Id: I7a652f42d149acbcb52cdb98e1f73a0e600d97db