Sketch the yolo wasm example. (#546)

* Sketch the yolo wasm example.

* Web ui.

* Get the web ui to work.

* UI tweaks.

* More UI tweaks.

* Use the natural width/height.

* Add a link to the hf space in the readme.

candle-wasm-examples/yolo/src/bin/app.rs

@@ -0,0 +1,5 @@
+fn main() {
+    wasm_logger::init(wasm_logger::Config::new(log::Level::Trace));
+    console_error_panic_hook::set_once();
+    yew::Renderer::<candle_wasm_example_yolo::App>::new().render();
+}