remove context from ui (again) and create weird trait for it

src/core/image.rs

@@ -15,7 +15,7 @@ impl Widget for Image {
     }
 }
 
-pub fn image<Ctx>(image: impl LoadableImage) -> impl WidgetFn<Image, Ctx> {
+pub fn image(image: impl LoadableImage) -> impl WidgetFn<Image> {
     let image = image.get_image().expect("Failed to load image");
     move |ui| Image {
         handle: ui.add_texture(image),