Add RoleConfig output

Add RoleConfig output

This exposes the deploy workflow for all roles from deploy-steps
via overcloud.j2.yaml - which means we can write it via the new
openstack overcloud config download command and/or run the workflow
outside of heat via mistral

With https://review.openstack.org/#/c/485732/ applied to
tripleoclient it becomes possible to do:

openstack overcloud config download --config-dir tmpconfig
cd tmpconfig/tripleo-EvEZk0-config
ansible-playbook -b -i /usr/bin/tripleo-ansible-inventory deploy_steps_playbook.yaml

This runs the deploy steps, exactly the same as normally run via heat
via ansible-playbook for all overcloud nodes (--limit can be used to restrict
to specific nodes/roles).

Change-Id: I96ec09bc788836584c4b39dcce5bf9b80e914c71