Adding multinode-3nodes-registry.yaml
Adding multinode-3nodes-registry.yaml

This file is part of tripleo-ci and we are moving it to tht/ci in
order to reduce the dependence of tripleo-ci repository so developers
can reproduce easily the jobs upstream.

Change-Id: Id62ab0ce1d77a0006e6fed2087735173245f1c2d

openstack/tripleo-heat-templates,openstack/tripleo-heat-templates,dprince/tripleo-heat-templates,dprince/tripleo-heat-templates