ipatests: add TestReplicaPromotionLevel0 to nightly runs
    
    Test class TestReplicaPromotionLevel0 was missing in nightly definition.
    
    Omitting the following classes as they are expectedly failing on
    Fedora 27:
    * TestKRAInstall
    * TestCAInstall
    * TestReplicaManageCommands
    * TestOldReplicaWorksAfterDomainUpgrade
    
    Reviewed-By: Florence Blanc-Renaud <flo@redhat.com>