Move our IRC channels to libera.chat

[Romain Bouvier]

Hi all,

You may be aware of Freenode IRC latest news.
TL;DR : There has been an ownership dispute over the freenode.net network. The dispute led to the
exodus of most former freenode staff from the network and the founding of a new network:
libera.chat. Lot of other communities already migrated off of freenode (archlinux, gentoo, ubuntu,
osuosl, fosdem to name a few)

Our official IRC channels (#xfce and #xfce-dev) have been migrated to irc.libera.chat too. A web
irc interface is available at https://web.libera.chat/#xfce :) Links and documentations have been
updated. Please update your IRC client config ! :)

Enjoy,

Romain,