Make Basic Marconi Docs Available

This blueprint aims to address the lack of cannonical, published documentation on Marconi. Here's some goals:

* Contact documentation PTL (Anne Gentle?) and determine standard OS doc procedure
* Ask about http://api.openstack.org/api-ref.html
* Write up introductory material
* Ultimately link up to existing code docs

Keep in mind: documentation has multiple audiences - it's more than just about the code. (deployment, extension, use, vision, purpose, the why of the thing, etc.)