AC-2461: Implement email and newsletter template compatibility CLI check

Author: nathanjosiah

app/code/Magento/Email/Console/Command/DbTemplateCheckCommand.php renamed to app/code/Magento/Email/Console/Command/DatabaseTemplateCompatibilityCommand.php

@@ -0,0 +1,20 @@
+<?php
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+
+declare(strict_types=1);
+
+namespace Magento\Email\Test\Unit\Model\Template;
+
+use Magento\Framework\TestFramework\Unit\Helper\ObjectManager;
+use PHPUnit\Framework\TestCase;
+
+class VariableCompatibilityCheckerTest extends TestCase
+{
+    public function testCompatibilityCheck()
+    {
+        $checker = new
+    }
+}