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/01-app-demos/ecommerce-site/src/components/error.rs

@@ -0,0 +1,14 @@
+use dioxus::prelude::*;
+
+#[component]
+pub fn error_page() -> Element {
+    rsx! {
+        section { class: "py-20",
+            div { class: "container mx-auto px-4",
+                div { class: "flex flex-wrap -mx-4 mb-24 text-center",
+                    "An internal error has occurred"
+                }
+            }
+        }
+    }
+}