desktop-goodies: irssi: notify.pl: track pids

Track pids of irssi instances so they can be used by irssi-notify-show helper.

Signed-off-by: Aliaksei Katovich <aliaksei.katovich@gmail.com>
desktop-goodies: irssi-notify-show: irssi windows

Handle only irssi windows that match any of ~/.irssi/pids

Signed-off-by: Aliaksei Katovich <aliaksei.katovich@gmail.com>