CI: Switch to c9s container image on quay.io
Container images on registry.gitlab.com fall under the proposed storage limitation of 10GB per repo. Prepare for that by moving all builder container image use to quay.io.
Bugzilla: INTERNAL
Upstream Status: RHEL-only
Signed-off-by: Michael Hofmann mhofmann@redhat.com
Edited by Michael Hofmann