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.
Reviewed-By: Florence Blanc-Renaud <frenaud@redhat.com>