Deploys a bifrost container using kolla-ansible bifrost-deploy.

IPA and disk images are downloaded rather than built to improve
reliability.

Currently only minimal testing of the deployment is performed, creating
and deleting an ironic node. Ideally we would perform a bare metal node
deployment.

The job is based on CentOS, as Ubuntu bifrost deployment is currently
failing with a python-MySQLdb error.

Change-Id: Ic45094594c21116b5b0d6a606f568fc7954175e3