Create RAML and/or Swagger file describing Admin API

[brylie]

Create an Admin API description file in either Swagger or RAML format. Restlet Studio can be used to visually design this file.

Definition of done

• Demonstrate comprehension of existing Admin API structure
• Create Swagger or RAML file describing all Admin API endpoints, methods, parameters, etc

[brylie]

There is a related issue on the API Umbrella issue queue.