prepare template for timestamps

_includes/footer.html

@@ -10,6 +10,10 @@
 
           {% comment %}This is used to generate share URL for howto-pages{% endcomment %}
           <div class="footer-text-container">
+          {% if page.timestamp %}
+            <p>Last page modification: {{ page.timestamp }}</p>
+          {% endif %}
+
           {% if page.shortcut %}
               <p>
                   Share this page:
@@ -44,4 +48,4 @@
   </footer>
   {% if site.siteID > 0 %}
       {%- include gdpr-banner.html -%}
-  {% endif %}
\ No newline at end of file
+  {% endif %}