KDE live images for Rawhide are now built with Kiwi, so let's do
it that way in openQA too (including for stable releases because
it's awkward to do it any other way). Kiwi build steps are almost
the same whatever you're building, so convert the container build
test into a generic Kiwi build test and use it for both. mock
setup is shared between Kiwi and LMC, so let's factor it out.
Signed-off-by: Adam Williamson <awilliam@redhat.com>
