Foreman 3.9 branching process

In the last meeting we decided to wait for Pulp 3.39 (Release Teem Meeting 2023-11-22 - #3 by ekohl). Due to the US holidays this was complicated a bit, mostly because we didn’t have anyone to merge the Katello PR itself. Thankfully @jeremylenz did that, which set the update in motion. In Fixes #36902 - Support Pulpcore 3.39, drop older versions by ianballou · Pull Request #315 · theforeman/puppet-pulpcore · GitHub we had some discussion, but that was mostly unrelated issues.

The current status is that the pipeline failed: