Support OpenApiBuilder flow

[Averios]

The old plugin allows us to define OpenAPI documentation on runtime.
Example:

OpenApiDocumentation getPriceByProductId =
            OpenApiBuilder.document()
                    .queryParam("productId", String.class)
                    .json("200", Price.class);

ApiBuilder.get(
                "/products/{productId}/price",
                OpenApiBuilder.documented(
                        getPriceByProductId, priceByProductIdHandler());

It would be nice to also have this option on Javalin 5.

[dzikoysk]

This is slightly out of scope at this moment to cover full specification with dedicated builder, because we're focused on compile-time specification. Even tho, it's still possible to use other libraries (e.g. https://github.com/derveloper/kotlin-openapi3-dsl ) and integrate them with our plugins:

javalin-openapi/examples/javalin-gradle-kotlin/src/main/java/io/javalin/openapi/plugin/test/JavalinTest.java

Lines 120 to 123 in 947ffce

	.withDefinitionProcessor(content -> { // you can add whatever you want to this document using your favourite json api
	content.set("test", new TextNode("Value"));
	return content.toPrettyString();
	}))

If you don't want use compile-time annotations, you can also replace builder with raw json/yaml specification.

[dzikoysk]

I'll mark it as enhancement request for now - it'll require some work to port current implementation into serializable dto structure, but I guess it could be also a healthy change for current impl.

[Averios]

Thank you, I'll try to check on how to use DefinitionProcessor for now