This adds a program, zookeeper-statsd, which monitors zookeeper
metrics and reports them to statsd. It also adds a container to
run that program. And it runs the container on each of the
ZooKeeper quorum members. And it updates the graphite host to
allow statsd traffic from quorum members. And it updates the
4-letter-word whitelist to allow the mntr command (which is used
to gather metrics) to be issued.
Change-Id: I298f0b13a05cc615d8496edd4622438507fc5423
96bac7b486