faster spreadsheet exporter based on opensout and other export improvements (#5238)

src/Export/Package/CellFormatter/ArrayFormatter.php

@@ -0,0 +1,22 @@
+<?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\Export\Package\CellFormatter;
+
+final class ArrayFormatter implements CellFormatterInterface
+{
+    public function formatValue(mixed $value): mixed
+    {
+        if (!\is_array($value)) {
+            throw new \InvalidArgumentException('Only arrays are supported');
+        }
+
+        return implode(', ', $value);
+    }
+}