Correct configuration of imap plugins

roles/mailserver/tasks/dovecot.yml

   template: src=etc_dovecot_conf.d_15-lda.conf.j2 dest=/etc/dovecot/conf.d/15-lda.conf
   notify: restart dovecot
 
+- name: Template 20-imap.conf
+  template: src=etc_dovecot_conf.d_20-imap.conf.j2 dest=/etc/dovecot/conf.d/20-imap.conf
+  notify: restart dovecot
+
 - name: Template dovecot-sql.conf.ext
   template: src=etc_dovecot_dovecot-sql.conf.ext.j2 dest=/etc/dovecot/dovecot-sql.conf.ext
   notify: restart dovecot

roles/mailserver/files/etc_dovecot_conf.d_20-imap.conf → roles/mailserver/templates/etc_dovecot_conf.d_20-imap.conf.j2

 protocol lmtp {
   # Space separated list of plugins to load (default is global mail_plugins).
   mail_plugins = $mail_plugins sieve
-  postmaster_address = postmaster@{{domain}}
+  postmaster_address = postmaster@{{ domain }}
 }