wip: overhaul event system

packages/html/src/events/animation.rs

@@ -0,0 +1,7 @@
+#[cfg_attr(feature = "serialize", derive(serde::Serialize, serde::Deserialize))]
+#[derive(Debug, Clone)]
+pub struct AnimationEvent {
+    pub animation_name: String,
+    pub pseudo_element: String,
+    pub elapsed_time: f32,
+}