Create a Fedora-CI plan repository

[lachmanfrantisek]

The goal of this is to have one repository with tmt plans to be run via Packit as a dist-git CI.

• Plan decision/management is done outside of Packit codebase.
• If available, this can be stored on Fedora-managed Forgejo instance.
• Checks can be either imported or stored directly in the repo.
• For now, whole Packit team should have access, later we can move this to a Fedora-CI SIG (once/when it's revamped.)
• The main (and only) audience is Packit dist-git PR CI.

Question(s) to resolve:

• Should we have a branching schema similar to Fedora packages?