Add Fernando's script for turning "deploy" messages into NOTICE

Retrieved from
https://raw.github.com/bucciarati/irssi-script-msg_to_notice/master/msg_to_notice.pl,
see
https://github.com/bucciarati/irssi-script-msg_to_notice/blob/master/msg_to_notice.pl
Merge remote-tracking branch 'git-booking-mirror/master'

Bring in changes I pushed to the git-booking-mirror.