Create unified notification system

core/static/bundled/utils/notifications.ts

@@ -0,0 +1,24 @@
+export enum NotificationLevel {
+  Error = "error",
+  Warning = "warning",
+}
+
+export function createNotification(message: string, level: NotificationLevel) {
+  const element = document.getElementById("notifications");
+  if (element === null) {
+    return false;
+  }
+  return element.dispatchEvent(
+    new CustomEvent("notification-add", {
+      detail: { text: message, tag: level },
+    }),
+  );
+}
+
+export function deleteNotifications() {
+  const element = document.getElementById("notifications");
+  if (element === null) {
+    return false;
+  }
+  return element.dispatchEvent(new CustomEvent("notification-delete"));
+}