Sync RHEL9 Dockerfiles to regular Dockerfiles

During the rhel9 migration we ended up duplicating our Dockerfiles with .rhel9 variants, so that we could stage the migration and not break CI in the process.

Now we should clean up and consolidate that duplication (again without breaking CI).

First step is to copy the .rhel9 Dockerfiles back over the currently-unused originals, then updated openshift/release to point to the original dockerfiles, then remove the .rhel9 variants.