ipatests: add missing classes from test_installation to nightly runs
    
    The following test classes were missing in nightly_ipa-4-6.yaml:
    * TestInstallWithCA_KRA1
    * TestInstallWithCA_KRA2
    * TestInstallWithCA_KRA_DNS1
    * TestInstallWithCA_KRA_DNS2
    * TestADTrustInstall
    * TestADTrustInstallWithDNS_KRA_ADTrust
    
    Reviewed-By: Florence Blanc-Renaud <flo@redhat.com>