Suggestion: groups and sub-routing

[cardinalby]

Hi! Thanks for the great library, I believe it's the best approach to documenting API in Go ecosystem so far.

Although, I found a batch of issues created by different people here regarding:

• groups (how to define several routing groups with different set of middlewares?)
• sub-routing (how to define sub-route group that will prefix all operations and keep auto-generated operation ids and summaries relevant)

Also, some of the features (Transformers) are available only globally for the API instance and can't be set per operation.

OpenAPI endpoints are registered directly with Adapter and I can't apply middlewares to them (how to add auth for openapi.yml endpoint?)

I believe these issues should be addressed by Huma instead of by tuning underlying routers:

• being aware of that things Huma can create proper operation ids and summaries
• it will be independent of router capabilities
• it would provide consistent user experience and nothing except std http.ServeMux would be needed for a user
• it would make easier to migrate from other routers

I want to use Huma in my company's project, we need all these features to migrate from Gin due to the project structure and heavy usage of gin groups.

I found an elegant way to provide all these features with Huma solely and want you to take a look at it. I believe it can be integrated into Huma with full backward compatibility resolving all the issues you have on Github.

Check out the library and contact me if you would be interested in bringing these features into Huma. I believe it would be even more elegant being a part of Huma rather than a separate library.

Some examples:

🔻 "Base path + tags + middlewares" group

v1gr := api.            // all operations registered with v1gr will have:
	AddBasePath("/v1").                            // - "/v1" base path
	AddOpHandler(op_handler.AddTags("some_tag")).  // - "some_tag" tag
	AddMiddlewares(m1, m2)                         // - m1, m2 middlewares
	
hureg.Get(v1gr, "/cat", ...) // "/v1/cat" with "some_tag" tag and m1, m2 middlewares
hureg.Get(v1gr, "/dog", ...) // "/v1/dog" with "some_tag" tag and m1, m2 middlewares

🔻 Multiple base paths

Sometimes we need to register the same endpoint with multiple base paths (e.g. /v1 and /v2).

multiPathGr := api.AddMultiBasePaths(nil, "/v1", "/v2")

hureg.Get(multiPathGr, "/sparrow", ...) // "/v1/sparrow"
                                        // "/v2/sparrow"

🔻 Transformers per group

trGr := api.AddTransformers(...) // transformers will be applied only to the operations 
                                 // registered in this group

hureg.Get(trGr, "/crocodile", ...)