more fullstack cleanups: loaders serialize, ServeConfig only (#4785)

* some opinionated cleanups in dioxus-server

* add serialize to loader

* add `result` to Resource

* clippy

* fix

* writable memos, resources, `onmount`, `.pending`, and `.value()` on actions

* fix compile issues

* fix typo

examples/07-fullstack/dog_app_self_hosted.rs

@@ -22,7 +22,7 @@ fn app() -> Element {
             }
         }
         div {
-            match breed.result() {
+            match breed.value() {
                 None => rsx! { div { "Click the button to fetch a dog!" } },
                 Some(Err(_e)) => rsx! { div { "Failed to fetch a dog, please try again." } },
                 Some(Ok(res)) => rsx! { img { max_width: "500px", max_height: "500px", src: "{res}" } },