Rename reqwest clients, mention cheap client clones in comment

src/appservice_server.rs

@@ -46,7 +46,7 @@ where
     *reqwest_request.timeout_mut() = Some(Duration::from_secs(30));
 
     let url = reqwest_request.url().clone();
-    let mut response = globals.reqwest_client().execute(reqwest_request).await?;
+    let mut response = globals.default_client().execute(reqwest_request).await?;
 
     // reqwest::Response -> http::Response conversion
     let status = response.status();