Add Form preview rudimentary component

[MAILPOET-2602]

assets/js/src/common/preview.jsx

@@ -0,0 +1,19 @@
+import React from 'react';
+import PropTypes from 'prop-types';
+
+
+function Preview({
+  children,
+}) {
+  return (
+    <>
+      {children}
+    </>
+  );
+}
+
+Preview.propTypes = {
+  children: PropTypes.node.isRequired,
+};
+
+export default Preview;