Using Let's Encrypt with UnrealIRCd

Introduction
TODO: expand

Use LE certificate & key via set::ssl::certificate and set::ssl::key.

Then use the self-signed certificate and key via listen::ssl-options on the dedicated server port (=incoming server connections) and cert/key via link::outgoing::ssl-options (=outgoing server connection).

This only works on UnrealIRCd 4.0.10+

Why this tutorial has not been written yet

 * Let's Encrypt requires you to run a webserver or use the 'standalone' option. This is solvable but a bit of a hassle.
 * Most IRC networks use DNS Round Robin (RR). Users can connect both by the individual server name (eg: irc1.test.net) and the round robin name (eg: irc.test.net). Let's Encrypt makes it really difficult to acquire and renew certificates for DNS RR names. If you want to acquire a certificate on server A, you have to run a command on server B, C and D also. Not just initially but also for your XX day renewal. Argh!

There are a number of "how to authenticate to Let's Encrypt" options. One of them being DNS TXT record to confirm ownership. You would think this would solve above cases but it does not: you would have to change the DNS TXT record every time you renew your <90 day certificate.