[REF] move event_bus into utils, readd 2 functions

src/utils.ts

@@ -0,0 +1,23 @@
+export class EventBus extends EventTarget {
+  trigger(name: string, payload?: any) {
+    this.dispatchEvent(new CustomEvent(name, { detail: payload }));
+  }
+}
+
+export function whenReady(fn?: any): Promise<void> {
+  return new Promise(function (resolve) {
+    if (document.readyState !== "loading") {
+      resolve(true);
+    } else {
+      document.addEventListener("DOMContentLoaded", resolve, false);
+    }
+  }).then(fn || function () {});
+}
+
+export async function loadFile(url: string): Promise<string> {
+  const result = await fetch(url);
+  if (!result.ok) {
+    throw new Error("Error while fetching xml templates");
+  }
+  return await result.text();
+}