Serv + Swagger2

[tel]

Swagger is a currently popular API description format (at least for JSON APIs). Serv is uniquely well-suited to auto-definition of Swagger description data due in part to the ways it follows Servant and also due to capturing the StatusCodes at each Endpoint.

In order to put the Api types through the wringer we should implement a function

swagger :: forall (a :: Api Nat Symbol *) . Sing a -> Swagger

along with whatever new annotation affordances and typeclasses are needed to make swagger work.