Made footer text configureable

ref #36

src/templates/runner_certificate.html

@@ -92,9 +92,7 @@
     </main>
     <footer class="certificate-footer">
       <p>
-        Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et
-        dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet
-        clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet.
+        {{../donations_footer_text}}
       </p>
     </footer>
   </article>