Intent to deprecate Jabber server

[Bartłomiej Piotrowski <bpiotrowski gnome org>]

Hello,

During routine infrastructure review, we found out that our Jabber
server usage is very low, i.e. fewer than 5 users login regularly. We
would like to shut it down, but as we could have missed some serious use
case, we would like to give the community a heads up.

Please reach out within 2 weeks if there is a reason to keep it running.

Bart