Rework os-release and issue mechanism
    
    Avoids upgrade issues such as competing fedora-release-$EDITION packages
    Makes a non-product install persistent (it won't be converted to an Edition
    install if something pulls in a fedora-release-$EDITION package
    
    Known issues: Right now, the RPM transaction solver always installs the
    fedora-release-$EDITION packages immediately after the fedora-release
    package, but it's unsafe to assume this. If this logic ever changes,
    there might be a gap for initial installation from anaconda where packages
    installed between fedora-release and fedora-release-$EDITION might end up
    with non-product defaults instead of productized ones. This is no
    different from the behavior prior to this patch, but it is not fixed by
    this patch. However, this problem was also previously vulnerable on
    upgrades, which will not be after this patch.