Retire old gitlab-02 VM on the fsn cluster

Now that the migration of gitlab to the dal cluster is done (tpo/tpa/issues#41431) we need to plan for the destruction of the old VM.

We want to keep it in place for some time just to make sure that everything is OK on the other side before destroying the data on the previous location.

Command to run to schedule the deletion of the old instance:

fabric-tasks$ fab -H gitlab-02.torproject.org ganeti.retire --master-host=fsn-node-01.torproject.org