Add simple components for Sidebar, Header and Form Title

[MAILPOET-2450]

assets/js/src/form_editor/components/header.jsx

@@ -0,0 +1,22 @@
+import React from 'react';
+import { IconButton } from '@wordpress/components';
+
+export default () => (
+  <div className="edit-post-header">
+    <div className="edit-post-header-toolbar" />
+    <div className="edit-post-header__settings">
+      <button
+        type="button"
+        className="components-button editor-post-publish-panel__toggle is-button is-primary"
+      >
+        Save
+      </button>
+      <IconButton
+        icon="admin-generic"
+        label="Settings"
+        onClick={() => null}
+        isToggled
+      />
+    </div>
+  </div>
+);