PULP_MANIFEST for discovery on downloads.theforeman.org

[dgoetz]

In https://community.theforeman.org/t/questions-on-downloads-theforeman-org/42010/ I promised an issue for this request.

I would like support for this being a possible file repository for use with pulp. So at least /discovery/releases/latest and /discovery/nightly would need to include a PULP_MANIFEST, perhaps all the directories. Should be quite simple to implement and is a good case of dogfooding in my opinion.

If the system runs EL9 implementing it would be like adding the pulpcore repository, installing pulp-manifest, and then run pulp-manifest for every directory we want to support. If it runs another operating system a pip install of pulp-manifest or even creating a script which just creates the data is also simple.