Adding deployment of Overcloud using tuskar

Adding tuskar deployment as alternative in
instack-deploy-overcloud script.
what is the long term plan to avoid the sed's? Ideally, we want CI to test what a user would do when using tuskar CLI. We don't want to have to tell them to use generate-keystone-pki, then edit or sed the file b/c generate-keystone-pki doesn't do the right thing.