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/mailman/tasks/main.yml

@@ -21,11 +21,10 @@
   loop:
     - aliases
     - milter_header_checks
-    - transport
   notify: run postmap
 
 - name: install postfix templated maps
-  template: src={{ item }} dest=/etc/postfix/{{ item | regex_replace('\.j2$', '') }} owner=root group=root mode=0644
+  template: src={{ item }}.j2 dest=/etc/postfix/{{ item }} owner=root group=root mode=0644
   loop:
     - transport
   notify: run postmap