[fuzon-http] OpenAPI spec integration

[supermaxiste]

Currently we're following a pretty solid and future-proof API format. In order to further standardize the API and follow best practices, we should follow the OpenAPI specification.

Example libraries that could help in the task:

• All-in-one: paperclip (warning: WIP)
• Documentation: utoipa

Note: based on OpenAPI.tools some tools might support different OpenAPI versions, we should watch out and make sure we're supporting the latest.

[cmdoret]

apistos looks good as well.

utoipa and apistos both generate OpenAPI v3 docs and support scalar, a modern UI (alternative to swagger) to interactively render openapi docs in the browser.

I think the choice comes down to how easy it will be to integrate either of these with the code.

(paperclip does not support openapi v3)

[cmdoret]

They both have a "simple-todo" example with actix web. At first sight, apistos looks more intuitive:

• utoipa: https://github.com/juhaku/utoipa/blob/master/examples/todo-actix/src/main.rs
• apistos: https://github.com/netwo-io/apistos/blob/main/examples/simple-todo/src/main.rs