Feat: add global context functions

Add functions like window() and router() to
allow dynamically grabbing global contexts
without have to use the hook variants.

Deprecates the existing hook variants to
discourage folks from adding more noise
to their codebases.

examples/eval.rs

@@ -5,26 +5,21 @@ fn main() {
 }
 
 fn app(cx: Scope) -> Element {
-    let eval_provider = use_eval(cx);
-
-    let future = use_future(cx, (), |_| {
-        to_owned![eval_provider];
-        async move {
-            let eval = eval_provider(
-                r#"
+    let future = use_future(cx, (), |_| async move {
+        let eval = eval(
+            r#"
                 dioxus.send("Hi from JS!");
                 let msg = await dioxus.recv();
                 console.log(msg);
                 return "hello world";
             "#,
-            )
-            .unwrap();
+        )
+        .unwrap();
 
-            eval.send("Hi from Rust!".into()).unwrap();
-            let res = eval.recv().await.unwrap();
-            println!("{:?}", eval.await);
-            res
-        }
+        eval.send("Hi from Rust!".into()).unwrap();
+        let res = eval.recv().await.unwrap();
+        println!("{:?}", eval.await);
+        res
     });
 
     match future.value() {