232 vagrant provider full

This augments @mboersma's recent branch to support running Deis in a Vagrant environment. The difference being that it uses celery tasks to programatically create nodes in the same way that other providers do.

The biggest point to note is that this approach requires the host machine to have an SSH server to accept commands from the Controller in order to manage Vagrant on the host.

However, this branch also contains some other things that make developing in a local environment easier:

* A detailed README with generic tips for developing on Deis.
* A Chef Server Vagrantfile.
* A `Vagrantfile.local` that allows you to customise your Chef Controller. Such as mounting the codebase onto the VM so you can use your favourite code editor on your host machine.