Request ODCS compose with all RPMs installed in the *unshipped* container image.
    
    So far, Freshmaker rebuilds just shipped container images, but for release-driver
    use-case, it needs to be able to rebuild also unshipped container images.
    
    Such images can contain unshipped RPMs, so our normal way of getting them from
    Pulp repositories defined by content sets will not work - Pulp repos don't
    contain unshipped RPMs.
    
    In this PR, we therefore request ODCS compose with all the RPMs installed
    in the unshipped container image and use it together with Pulp repos. Using
    this approach, unshipped container image can get even the so-far unshipped RPMs.