added event to extend detail pages (#3209)

src/Event/ProjectDetailControllerEvent.php

@@ -0,0 +1,30 @@
+<?php
+
+/*
+ * This file is part of the Kimai time-tracking app.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace App\Event;
+
+/**
+ * Triggered for project detail pages, to add additional content boxes.
+ *
+ * @see https://symfony.com/doc/5.4/templates.html#embedding-controllers
+ */
+final class ProjectDetailControllerEvent extends AbstractProjectEvent
+{
+    private $controller = [];
+
+    public function addController(string $controller): void
+    {
+        $this->controller[] = $controller;
+    }
+
+    public function getController(): array
+    {
+        return $this->controller;
+    }
+}