Add common interface

Author: jissereitsma

Form/ItemConvertorInterface.php

@@ -0,0 +1,13 @@
+<?php
+declare(strict_types=1);
+
+namespace Loki\AdminComponents\Form;
+
+use Magento\Framework\DataObject;
+use Magento\Framework\View\Element\Block\ArgumentInterface;
+
+interface ItemConvertorInterface extends ArgumentInterface
+{
+    public function afterLoad(DataObject $item): DataObject;
+    public function beforeSave(DataObject $item): DataObject;
+}