ipatests: add test_trust suite to nightly runs
    
    The test suite test_trust was missing in nightly definitions
    because PR-CI was not able to provision multi-AD topology.
    Now that PR-CI is updated, we can start executing this test suite.
    It is not reasonable to add it to gating as this suite is
    time consuming like other tests requiring provisioning of AD instances.
    
    Signed-off-by: Sergey Orlov <sorlov@redhat.com>
    Reviewed-By: Florence Blanc-Renaud <flo@redhat.com>