A replacement macro for rocket::routes. The key differences are that this macro will add an
additional element to the resulting Vec<rocket::Route>, which serves a static file called
openapi.json. This file can then be used to display the routes in the swagger ui.
A proc macro to be used in tandem with one of Rocket's endpoint macros. It requires that all
of the arguments of the route implement one of the traits in rocket_okapi::request, and that
the return type implements OpenApiResponder.