Clean up expired invitations

See OpenConext/OpenConext-Invite#681

Author: oharsta

roles/invite/templates/serverapplication.yml.j2

@@ -84,6 +84,8 @@ cron:
   metadata-resolver-url: "https://metadata.{{ base_domain }}/idps-metadata.xml"
   # A value of 0 means no logs will be deleted
   purge-audit-log-days: 365
+  # A value of 0 means no invitations will be deleted
+  purge-expired-invitations-days: 365
 
 myconext:
   uri: "https://login.{{ myconext_base_domain }}/myconext/api/invite/provision-eduid"