This reduces the legacy 'pungi' script to only its gather phase,
and removes related stuff in gather.py. The gather phase is used
in the yum path through phases/gather/methods/method_deps.py, so
it cannot be entirely removed until all users of that are gone.
But we can at least get rid of the non-Koji support for creating
install trees, ISOs and repos.
Merges: https://pagure.io/pungi/pull-request/1793
Signed-off-by: Adam Williamson <awilliam@redhat.com>
3bc35a9a27