* Add 'http' port specification to zookeeper statefulset
This makes the zookeeper spec inline with the other statefulset specs
in this chart and it provides a port target for custom podMonitors
* Added PodMonitors for bookie, broker, proxy, and zookeeper
New PodMonitors are needed for prometheus-operator to pickup scrape
targets.
Defaults to disabled so users need to opt in to deploy
* Added Apache license info to podmonitor yamls
