tripleo deploy multinode

Add support for using openstack tripleo deploy to deploy multinode overclouds. Largely, it is already possible today, however there is some set of features that may not work or be supported, and this blueprint is meant to identify and track those features, as well as add documentation and supporting material.

CI may be a possibility, but it would require adding a multinode job, so is likely not ideal due to resource capacity.

There are some workflows/playbooks that rely on Swift on the undercloud. As Swift won't be present in a multinode deployment using tripleo deploy, this will also track adding the interfaces to those playbooks so that the Swift portion is pluggable with a different mechanism.