Initial changes testing and running vue3

v2client-vite-vue3/src/EventBus.js

@@ -0,0 +1,12 @@
+import mitt from 'mitt'
+
+const emitter = mitt()
+
+// Preserves the Vue 2 $on/$emit/$off API used throughout the codebase
+const EventBus = {
+	$on:   (...args) => emitter.on(...args),
+	$off:  (...args) => emitter.off(...args),
+	$emit: (...args) => emitter.emit(...args),
+}
+
+export default EventBus