ipatests: Add nightly definitions for enforcing mode
    
    Duplicates the scenario for nightly_ipa-4-8_latest.yaml and
    sets `selinux_enforcing` parameter as True.
    
    Indentation for all definitions have been fixed.
    
    Issue: freeipa/freeipa-pr-ci#391
    
    Signed-off-by: Armando Neto <abiagion@redhat.com>
    Reviewed-By: Florence Blanc-Renaud <frenaud@redhat.com>