Axum 0.7 support

[tamasfe]

Closes #87, closes #82.

I also fixed the inconsistencies between the router's <op> and <op>_with functions so that the former only calls the latter with a no-op closure, thus they cannot get out of sync.

I also changed the document generation defaults:

• Responses are now inferred by default, as this seems to be the most common use-case, and the route functions will respect the global setting (this was a bug before).
• Schema inlining is disabled by default, because schema collisions are fixed in Add schema_id(), handles different types with the same name GREsau/schemars#247.