Right now, one can't use the official fedora-bootc images for the custom
base image flow because it doesn't actually ship `bootc-base-imagectl`.
This will be fixed by the move to Konflux, but it's not clear when that
will happen.
Given how trivial it is to do, let's just ship it in the image for now.
Closes: https://gitlab.com/fedora/bootc/base-images/-/issues/44
