Add 15-dracut-fedora.conf, drop related patches
    
    Rather than patch osbuilder dracut files, drop in our own dracut
    conf file with Fedora specific additions.
    
    Rework the way we generate modules-load.d conf files in osbuilder.sh
    to handle this in a nicer way, which also has the benefit of ensuring
    modules-load.d doesn't fail if we specify a non-modularized driver
    
    Signed-off-by: Cole Robinson <crobinso@redhat.com>