Render static markdown files from Runbooks

[josh-padnick]

One useful use case for Runbooks is to create static markdown guides whose code snippets are known to be current.

There are a couple possible ways Runbooks could accomplish this:

1. Runbooks could pull code snippets from URLs. These could either be static code snippets or Boilerplate templates.
2. We could create a new subcommand, runbooks render which takes parameters for each of the Runbook's <BoilerplateInputs> variables, renders all code snippets accordingly, and then outputs a static guide. Presumably we would not render the web form itself in the static version of the markdown doc.