codify "platform" into resolution logic, server-fn/fullstack overhaul (#4596)

overhaul dioxus fullstack using a new implementation of server_fn

This PR is a complete rewrite of dioxus fullstack designed to improve compatibility with axum and to fix a number of compilation errors based on feature flag unification plumbing through macros.

examples/06-routing/link.rs

@@ -0,0 +1,81 @@
+//! How to use links in Dioxus
+//!
+//! The `router` crate gives us a `Link` component which is a much more powerful version of the standard HTML link.
+//! However, you can use the traditional `<a>` tag if you want to build your own `Link` component.
+//!
+//! The `Link` component integrates with the Router and is smart enough to detect if the link is internal or external.
+//! It also allows taking any `Route` as a target, making your links typesafe
+
+use dioxus::prelude::*;
+
+const STYLE: Asset = asset!("/examples/assets/links.css");
+
+fn main() {
+    dioxus::launch(app);
+}
+
+fn app() -> Element {
+    rsx! (
+        Stylesheet { href: STYLE }
+        Router::<Route> {}
+    )
+}
+
+#[derive(Routable, Clone)]
+#[rustfmt::skip]
+enum Route {
+    #[layout(Header)]
+        #[route("/")]
+        Home {},
+
+        #[route("/default-links")]
+        DefaultLinks {},
+
+        #[route("/settings")]
+        Settings {},
+}
+
+#[component]
+fn Header() -> Element {
+    rsx! {
+        h1 { "Your app here" }
+        nav { id: "nav",
+            Link { to: Route::Home {}, "home" }
+            Link { to: Route::DefaultLinks {}, "default links" }
+            Link { to: Route::Settings {}, "settings" }
+        }
+        Outlet::<Route> {}
+    }
+}
+
+#[component]
+fn Home() -> Element {
+    rsx!( h1 { "Home" } )
+}
+
+#[component]
+fn Settings() -> Element {
+    rsx!( h1 { "Settings" } )
+}
+
+#[component]
+fn DefaultLinks() -> Element {
+    rsx! {
+        // Just some default links
+        div { id: "external-links",
+            // This link will open in a webbrowser
+            a { href: "http://dioxuslabs.com/", "Default link - links outside of your app" }
+
+            // This link will do nothing - we're preventing the default behavior
+            // It will just log "Hello Dioxus" to the console
+            a {
+                href: "http://dioxuslabs.com/",
+                onclick: |event| {
+                    event.prevent_default();
+                    println!("Hello Dioxus")
+                },
+                "Custom event link - links inside of your app"
+            }
+        }
+    }
+}