Mailman: set default list footer

Add links to the list archive and guidelines to the default footer.

https://pagure.io/fedora-infrastructure/issue/6794

roles/mailman/files/mailman-generic-list-footer

@@ -0,0 +1,6 @@
+_______________________________________________
+$display_name mailing list -- $listname
+To unsubscribe send an email to ${short_listname}-leave@${domain}
+Fedora Code of Conduct: https://getfedora.org/code-of-conduct.html
+List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines
+List Archives: ${hyperkitty_url}

roles/mailman/tasks/main.yml

@@ -196,6 +196,14 @@
   notify:
     - restart mailman3
 
+- name: set default list footer
+  copy: src=mailman-generic-list-footer
+            dest=/var/lib/mailman3/templates/site/en/list:member:generic:footer
+            owner=mailman group=mailman mode=0644
+  tags:
+  - config
+  - mailman
+
 
 #
 # Crontab