Add a base mojom file to contain empty mojom definitions of libcamera objects, as well as documentation for the IPA interfaces that need to be defined in the mojom files. Signed-off-by: Paul Elder <paul.elder@ideasonboard.com> Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>