galaxy_ng: ensure compilemessages during builds

context: https://github.com/ansible/galaxy_ng/pull/1015 - we merged updated po files for l10n

But updating `.po` files doesn't affect the API until these get compiled into `.mo` files
these are gitignored, which makes sense, but then we need to run `pulpcore-manager compilemessages` to regenerate them.

I do not know if there's already production tooling to run that, Christian Adams suggested https://gitlab.cee.redhat.com/automation-hub/packaging/-/blob/master/roles/publish/tasks/build_galaxy_ng.yml#L20 might be a good place for it

I do know development does NOT do this, and seems to be missing the gettext rpm package (no msgfmt).

=> ensure compilemessages happens during any dev/prod build

Cc awcrosby5, dnewswan