Work out package delivery mechanism

Directly installing from the CBS Koji repositories does not quite work because they are merged with the external C9S repository, and we sometimes have external builds overtaking us.

For example, we have both pcre-8.44-3.el9.3.x86_64 and pcre-8.44-3.el9sopt_901.3.x86_64 in the repository, but the non-rebuilt version is larger:

$ rpmdev-vercmp  8.44-3.el9.3 8.44-3.el9sopt_901.3
8.44-3.el9.3 > 8.44-3.el9sopt_901.3

And of course it can happen that regular Stream development adds a new build, which has a higher release number and is therefore preferred.

In either case, even dnf distro-sync does not pick up the rebuild.

Cutting external repository inheritance would fix this, but it also impact the buildroot. Right now, it is not sufficiently complete for that. Maybe there are other options.