Update file footer_custom.html

_includes/footer_custom.html

-footer_content: >
-  <div style="text-align: center; margin-bottom: 10px;">
-    <img src="/assets/logo/TUDelft Logo.png" alt="TU Delft Logo" style="height: 40px; width: auto;">
+footer_content: <div class="footer-logo">
+    <img src="{{ site.footer_logo | relative_url }}" alt="TU Delft Logo" style="height: 40px; width: auto;">
   </div>
   <div>
     The MUDE Team &copy; 2024 <a rel="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY 4.0</a>