Merge branch 'mailman' into 'master'

docs/ssh-hostkeys.txt

docs/ssh-known_hosts.txt

group_vars/all/vault_mailman.yml

host_vars/lists.archlinux.org

hosts

playbooks/lists.archlinux.org.yml

playbooks/luna.yml

playbooks/mail.archlinux.org.yml

roles/mailman/defaults/main.yml

roles/mailman/files/mailman.ini

roles/mailman/files/milter_header_checks

roles/mailman/handlers/main.yml

roles/mailman/tasks/main.yml

roles/mailman/templates/main.cf.j2

roles/mailman/templates/mm_cfg.py.j2

roles/mailman/templates/nginx.d.conf.j2

roles/mta_sts/defaults/main.yml

roles/postfix/files/mailman_compat

roles/postfix/handlers/main.yml

roles/postfix/tasks/main.yml