Camera: Add default 2.5 provider for legacy and external webcam HALs

Add 2.5 implementations, which do not support passthrough mode and
therefore doesn't need the HIDL_Fetch methods or a specially-named
-impl library in the /hw directory.  Instead, the service directly
instantiates the necessary service.

Also add VTS tests for the new notification

Test: Verify device state changes are logged by HAL
Test: Camera starts as usual with both 2.4 and 2.5 providers on
      walleye.  Camera CTS completes.
Test: New VTS tests pass
Bug: 121379978
Change-Id: I0fc99379eb7e01c5b2efb20afb5753bb6ce8b627