Removing foreman-devel, foreman-test and unused packages

More detail in the commit messages, but I'm removing foreman-devel and foreman-test as we only build them for Fedora today and I believe they're both unused and unusable.  I don't have the time or inclination to update them for Fedora, let alone build all of the necessary dependencies for SCL OSes.  (Some of the builds in the comps files simply don't exist anyway.)

I found a few more packages that aren't needed in our repos while doing this, which helps keep the maintenance burden low.