LinkRelay: sync config with Relay

Please see https://github.com/TkTech/notifico/issues/79

* > There is a difference between a NOTICE to a channel and a NOTICE to a user, every client should be able to correctly display notices to a channel. ~~ @Dav1dde

* > They should, but they don't. ~~ @Mkaysi

* > That's besides the point. There are a lot of clients that do handle it properly, and if they don't then that's not notifico's fault, that's their own fault. ~~ @sckasturi
LinkRelay/config.py: use PRIVMSG with non-PRIVMSG.

The world isn't ready for NOTICE yet, but there are many other things
wrong with the world too. Maybe some day.