Add stimulus controller to trigger GTM datalayers

public/typo3conf/ext/ep_theme/Resources/Private/Assets/js/controllers/datalayer_controller.js

@@ -0,0 +1,14 @@
+import { Controller } from 'stimulus'
+
+export default class extends Controller {
+
+    static values = [ 'event' ]
+
+    trigger() {
+        window.dataLayer = window.dataLayer || []
+        dataLayer.push({
+            'event': this.eventValue,
+        })
+    }
+
+}