Exibir código-fonte para IRedMail com Let's Encrypt

* http://www.iredmail.org/forum/topic10177-iredmail-support-will-there-be-integration-with-httpsletsencryptorg.html
* http://www.iredmail.org/docs/use.a.bought.ssl.certificate.html
* http://stackoverflow.com/questions/41129191/iredmail-ssl-using-lets-encrypt-certbot-auto
* https://www.readycat.net/uncategorized/mail-server-with-iredmail/
* http://doc.samplezone.ch/iredmail/version-0-9-2/ssl-tls-secure-communication/tls-ssl-starttls-iredmail/
* https://aminovadel.com/pamyatka/ustanovka-sertifikata-lets-encrypt-na-iredmail.html