Translations:Using Let's Encrypt with UnrealIRCd/2/en

The goal
After this guide you will have a dual certificate setup:
 * Clients will connect to your server and see the Let's Encrypt certificate (from /etc/letsencrypt/...). That way they will see a "real certificate" that is validated by trusted certificate authority
 * Server-to-server connections will use the self-signed certificates (from ~/unrealircd/conf/tls/server...). This makes things easy for server linking since the certificate/keys will stay the same (and not change every 30-90 days).