Add Rackspace support for dev-build-and-up

Adding basic Rackspace support for the dev-build-and-up.sh workflow. In general the workflow is very similar to gce but modified to work with `swiftly` and `nova` as well as change some assumptions about the available network.

A [README](docs/getting-started-guides/rackspace.md) is included that describes some of the differences between implementations.

Let me know if there are any questions.

Ryan