Add footer dev note

Signed-off-by: Pekka Helenius <fincer89@hotmail.com>

bookstore/src/main/resources/templates/fragments/footerpart.html

@@ -9,8 +9,10 @@ We allow broken URLs on development phase since the page is not deployed to the
 target domain environment. Once fully implemented, footer relative URLs should work.
 */-->
 
-<footer style="margin-top: 350px;" th:include="https://fjordtek.com/ :: footer">
-</footer>
+<div style="margin-top: 400px;">
+	<p>Dev note: This footer is fetched from an external URL and presented only for demonstration purposes.</p>
+	<footer th:replace="https://fjordtek.com/ :: footer"></footer>
+</div>
 
 <link rel="stylesheet" type="text/css" href="https://fjordtek.com/css/style.css">
 <link rel="stylesheet" type="text/css" href="https://fjordtek.com/css/style2.css">