Making nigthly test definition editable by FreeIPA's contributors
    
    Now the test definition of nightly tests will be on freeipa repo. The
    definition that's used on every PR (previously as .freeipa-pr-ci.yaml)
    is in ipatests/prci_definitions/gating and the .freeipa-pr-ci.yaml file
    is just a symlink to the real file.
    
    In the same dir there is also nightly_master and nightly_rawhide, both
    to be used in nightly tests.
    
    Divided test_topology.py into 3 subtests.
    
    Bumped vagrant template to version 0.1.6
    
    This PR is the result of discussion on freeipa-devel mailing list [1].
    
    [1] https://lists.fedoraproject.org/archives/list/freeipa-devel@lists.fedorahosted.org/message/4VAWJ4SFKKBFFICDLQCTXJWRRQHIYJLL/
    
    Reviewed-By: Michal Reznik <mreznik@redhat.com>
    Reviewed-By: Michal Reznik <mreznik@redhat.com>