gather: Expand wildcards in Pungi
    
    When the configuration lists `*` in `additional_packages`, it has a
    special meaning. If it's passed to fus directly, it will use it to match
    all modules and RPMs that are not masked by a package available in some
    default stream. Neither is good. We don't want it to match modules, and
    we want even the masked packages.
    
    The fix is to expand the wildcard to a list of NVRs and give that to
    fus. It should include the package even if it is masked.
    
    Signed-off-by: Lubomír Sedlář <lsedlar@redhat.com>