Optimize systemd dependency for containers
    
    According to https://fedoraproject.org/wiki/Packaging:Scriptlets:
    If a package is suitable for installation without systemd (in a
    container image, for example) and does not require any of the
    systemd mechanisms such as tmpfiles.d, then the systemd_ordering macro
    MAY be used instead of the systemd_requires macro.
    
    That is exactly the case we want to address for container images
    when installing packages in it.
    
    Resolves: rhbz#1668688
    Related-Bug: #1804822
    Signed-off-by: Bogdan Dobrelya <bdobreli@redhat.com>