Investigate integration with linch-pin

[jlebon]

It might make sense to call out to linch-pin for provisioning. This would allow users to define more complex topologies than possible now, as well as have an easy way to add support for more types of provisioners.

[cgwalters]

FWIW I more meant as a backend, at least initially. At some point I think we're likely to want to run some of the load in EC2/GCE, and that wouldn't be exposed to the consumer.