add aup to footer

Author: Mitchob

_data/footer.yml

@@ -1,11 +1,12 @@
 # see https://github.com/AustralianBioCommons/human-omics-data-sharing-field-guide/blob/main/_data/footer.yml
 copyright: Add copyright notice here!
-extra_line: Add other relevant information here!
 columns:
   - type: links
     width: 3
     children:
       - url_text: Home
         url: /
       - url_text: Contributors
-        url: /contributors
+        url: /contributors
+      - url_text: Acceptable Use Policy
+        url: /aup