added project importer and grandtotal converter (#1468)

src/Importer/UnsupportedFormatException.php

@@ -0,0 +1,20 @@
+<?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\Importer;
+
+use Throwable;
+
+class UnsupportedFormatException extends \Exception
+{
+    public function __construct(string $message, int $code = 0, Throwable $previous = null)
+    {
+        parent::__construct($message, $code, $previous);
+    }
+}