Bump warp and begin axum migration (#9001)

- Bump `warp` to 0.4. This unifies `warp` and `axum` onto the same `http`, `hyper`, `h2`, `rustls`, etc versions.
- Create `axum_utils` which contain common functions and types
- Begins migration of all HTTP API servers from warp to axum


Co-Authored-By: Mac L <mjladson@pm.me>

beacon_node/client/src/builder.rs

@@ -615,7 +615,7 @@ where
     /// If type inference errors are being raised, see the comment on the definition of `Self`.
     #[allow(clippy::type_complexity)]
     #[instrument(name = "build_client", skip_all)]
-    pub fn build(
+    pub async fn build(
         mut self,
     ) -> Result<Client<Witness<TSlotClock, E, THotStore, TColdStore>>, String> {
         let runtime_context = self
@@ -647,6 +647,7 @@ where
             let exit = runtime_context.executor.exit();
 
             let (listen_addr, server) = http_api::serve(ctx, exit)
+                .await
                 .map_err(|e| format!("Unable to start HTTP API server: {:?}", e))?;
 
             let http_api_task = async move {
@@ -677,6 +678,7 @@ where
             let exit = runtime_context.executor.exit();
 
             let (listen_addr, server) = http_metrics::serve(ctx, exit)
+                .await
                 .map_err(|e| format!("Unable to start HTTP metrics server: {:?}", e))?;
 
             runtime_context