Setup mailman3 server

We want to migrate to mailman3 as mailman2 is basically unmaintained and requires Python 2 which is EOL.

Because the mailman and mailman3 packages conflict and we don't want to perform a big bang migration, mailman3 must be deployed on a separate server. mailman-web (mailman3's web interface) hasn't been packaged yet, so for now we are using my homebrewed PKGBUILD.

[1] https://gist.github.com/klausenbusk/5982063f95c503754a51ed2fefb8915e

Ref #59 (closed)

---

Migrated lists:

• arch-announce
• arch-devops-private
• arch-events
• arch-wiki-admins

roles/mailman3/tasks/main.yml

@@ -62,8 +62,9 @@
   become_user: mailman-web
   when: install.changed
 
-- name: open firewall holes for mailman (LMTP)
-  ansible.posix.firewalld: port=8024/tcp zone=wireguard permanent=true state=enabled immediate=yes
+- name: open LMTP ipv4 port for lists.archlinux.org
+  ansible.posix.firewalld: zone=wireguard state=enabled permanent=true immediate=yes
+    rich_rule="rule family=ipv4 source address={{ hostvars['lists.archlinux.org']['wireguard_address'] }} port protocol=tcp port=8024 accept"
   tags:
     - firewall