Add support for interrogation of Helm-rendered documents

[craiganderson]

A typical ops use-case when troubleshooting a problem is to inspect the current running configs of components. For example, when investigating a neutron issue, one would want to examine the neutron.conf being used in the environment.

My understanding is that the shipyard API GET /v1.0/renderedconfigdocs would not provide the documents as rendered by Helm (neutron.conf, nova.conf, etc).

If this is the case, then adding this sort of capability to shipyard is something I think would be useful for operations and general debugging.

@alanmeadows @intlabs