Generate Swagger docs

[galvesribeiro]

ASP.Net Controllers has the ability to read [ProducesResponseType] and generate swagger.json which is used to renger Swagger documentation pages.

To support that Json generation we need:

• Add attributes that mimic that behaviour without having the MVC dependency
• Extend Swashbuckle package (create Swashbuckle.Orleans?) to read from those attributes and generate the swagger.json