gitlab-ci: Update to current templates

gitlab-ci: Update to current templates

The .fdo.container-ifnot-exists template has been replaced by
.fdo.container-build.

We need to include "debian/" in FDO_REPO_SUFFIX for now, we can drop it
for individual images when their tags are bumped if we want.

Miscellaneous other goodies this gets us:
* The templates now add some labels to images which may be useful for
  garbage collecting unused tags in the future.
* The templates now copy the current tag from the main project
  registry to the forked project's if it already exists in the latter
  but points to a different image hash. This will avoid false failures
  (or passes) due to using the wrong image.

Tested-by: Marge Bot <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4286>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4286>