Enhance OpenAPI generation

[SentryMan]

• fixes param openapi generation
• Adds an annotation we can use to add openapi responses with.

With this, we can define 4xx and 5xxx in our openapi and even have the correct schema for the error body

Adding with a 2xx code will override the default 2xx status code for the endpoint.

This is especially useful when people are using the Helidon ServerResponse/Javalin Context in void method controllers

Thoughts?

  /**
   * Standard Post
   *
   * @param b the body
   * @return the response body (from javadoc)
   */
  @Post("/post")
  @OpenAPIReturns(responseCode = "200", description = "from annotaion")
  @OpenAPIReturns(responseCode = "201")
  @OpenAPIReturns(responseCode = "400", description = "User not found")
  @OpenAPIReturns(
      responseCode = "500",
      description = "Some other Error",
      type = ErrorResponse.class)
  RequestModel testPost(RequestModel b) {
    System.out.println("got " + b);
    return new RequestModel("Hmmm, now that I think about it");
  }

This will generate

other endpoints...
  "/javalin/post" : {
      "post" : {
        "tags" : [ ],
        "summary" : "Standard Post",
        "description" : "",
        "requestBody" : {
          "description" : "the body",
          "content" : {
            "application/json" : {
              "schema" : {
                "$ref" : "#/components/schemas/RequestModel"
              }
            }
          },
          "required" : true
        },
        "responses" : {
          "200" : {
            "description" : "from annotaion",
            "content" : {
              "application/json" : {
                "schema" : {
                  "$ref" : "#/components/schemas/RequestModel"
                }
              }
            }
          },
          "201" : {
            "description" : "the response body (from javadoc)",
            "content" : {
              "application/json" : {
                "schema" : {
                  "$ref" : "#/components/schemas/RequestModel"
                }
              }
            }
          },
          "400" : {
            "description" : "User not found"
          },
          "500" : {
            "description" : "Some other Error",
            "content" : {
              "application/json" : {
                "schema" : {
                  "$ref" : "#/components/schemas/ErrorResponse"
                }
              }
            }
          }
        }
      }
    }

[rbygrave]

Yeah, looks right on the money - awesome, ta.