When constructing an output profile using --profile-from, it is useful
to be able to override the top level container profile.
Expose a --container-profile option that applies as an override after
other methods for constructing an output profile have run. If no other
method was used, this will result in an empty top level container.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/3977>
