Reorganize method routers for handlers and services (#405)

* Re-organize method routing for handlers

* Re-organize method routing for services

* changelog

examples/print-request-response/src/main.rs

@@ -7,8 +7,8 @@
 use axum::{
     body::{Body, BoxBody, Bytes},
     error_handling::HandleErrorLayer,
-    handler::post,
     http::{Request, Response, StatusCode},
+    routing::post,
     Router,
 };
 use std::net::SocketAddr;