OpenAPI Export for API Definition (Issue1178)

[uurl]

Tasks completed:

• Full and lossless conversion of any API Definition into a valid OpenAPI Specification.
• Tests at the unit and integration level which demonstrate the correctness of pieces and the whole.
• System tests that generate client libraries from the OpenAPI Spec, and interact to verify the client library works.
• Manual testing for complex scenarios.
• A new binding type for routes called "Swagger UI", which will use serve Swagger UI at the specified route, which are generated during API Definition update (if necessary) and stored for subsequent serving of the endpoint.

/claim #1178