We want to run the desktop upgrade tests on aarch64; to do that,
we need the required base images to be built. We also need to
do the `console=tty0 quiet` boot args for the desktopencrypt
image so the decrypt prompt is visible on boot; to handle this,
we extend the existing hack for using a release-specific ks
to be more generic and allow for a more specific kickstart by
arch, release or both.
Signed-off-by: Adam Williamson <awilliam@redhat.com>