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/09-reference/xss_safety.rs

@@ -0,0 +1,25 @@
+//! XSS Safety
+//!
+//! This example proves that Dioxus is safe from XSS attacks.
+
+use dioxus::prelude::*;
+
+fn main() {
+    dioxus::launch(app);
+}
+
+fn app() -> Element {
+    let mut contents = use_signal(|| String::from("<script>alert(\"hello world\")</script>"));
+
+    rsx! {
+        div {
+            h1 {"Dioxus is XSS-Safe"}
+            h3 { "{contents}" }
+            input {
+                value: "{contents}",
+                r#type: "text",
+                oninput: move |e| contents.set(e.value()),
+            }
+        }
+    }
+}