Gate the beta galaxy Prod deploy based on migrations/downtime

Gate the Community Prod deploy based on git diff between old and new commit, do not auto-deploy if there a change to `galaxy_ng/app/migrations/` or a y-stream change to `pulpcore`, `pulp_ansible`, or `pulp-container` in `setup.py` (which likely includes migrations). In this case the deploy requires downtime and/or read-replica process. This step can be relaxed depending on the work, adoption, and any automation of AAH-2196