Add annotation support

[arthurdm]

This issue will add OpenAPI v3 annotations that allow users to document their RESTful application. It should cover the entire spectrum of the OpenAPI v3 specification

[arthurdm]

Closing this issue as there has been many PRs that delivered this annotations in the past few weeks. We consider the current set of annotations very close to complete, with just a minor few bugs/enhancements, which will be tracked via individual issues.