Create standalone registry container for Helm

As part of our larger effort to create per-service container images (#2420 (closed)), we wanted to choose Registry as the first service to work on. This is primarily because it is the most loosely coupled, and so would be a good first step in investigating how to configure by itself.

A couple areas we will need to discuss:

1. What configuration was Omnibus performing to set up Registry?
2. Without relying upon Omnibus/chef, at least for the configuration on the Registry side, what should we use to apply and coordinate the settings?