Add rewrite rule to access specific parts of the mirrorlist
    
    The MM1 publiclist links are supposed to still work. If an old
    publiclist link tries to directly access a product/version or
    product/version/arch combination an additional 'mirrors' needs to be
    inserted into the link. For full MM1 compatibility following PR is
    necessary:
    
    https://github.com/fedora-infra/mirrormanager2/pull/76