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/window_zoom.rs

@@ -1,12 +1,10 @@
 use dioxus::prelude::*;
-use dioxus_desktop::use_window;
 
 fn main() {
     dioxus_desktop::launch(app);
 }
 
 fn app(cx: Scope) -> Element {
-    let window = use_window(cx);
     let level = use_state(cx, || 1.0);
 
     cx.render(rsx! {
@@ -16,7 +14,7 @@ fn app(cx: Scope) -> Element {
             oninput: |e| {
                 if let Ok(new_zoom) = e.value.parse::<f64>() {
                     level.set(new_zoom);
-                    window.webview.zoom(new_zoom);
+                    dioxus_desktop::window().webview.zoom(new_zoom);
                 }
             }
         }