Add 'tcpircbot' Puppet class

This Puppet class configures a Python script that listens on a TCP socket and
forwards incoming data to an IRC channel. It allows setting up automatic
announcements to IRC from machines in the cluster that do not have a public
interface. The script runs as an upstart service. By default, it connects to
freenode via SSL, and listens on port 9200 for messages to forward.

Sample configuration:

	include tcpircbot

	tcpircbot::instance { 'announcebot':
	  password => 'nickserv_secret123',
	  channel  => '#wikimedia-operations',
	}

If a "cidr" key is set, it is interpreted as an IPv6 CIDR range. Inbound
connections from addresses outside this range are rejected. If "cidr" is not
set, only private and loopback IP addresses are allowed to connect.

Change-Id: I6d4f661b70e6c4d4111672f5a7f8018389986a18