opensmtpd: support relaying mail

roles/opensmtpd/tasks/main.yml

@@ -1,7 +1,15 @@
+# this role is currently for alpine linux only
+
 - name: Install mail server
   package:
     name: opensmtpd
 
+- name: Configure mail server
+  template:
+    dest: /etc/smtpd/smtpd.conf
+    src: smtpd.conf.j2
+  notify: restart smtpd
+
 - name: Enable mail server
   service:
     name: smtpd