Add Perl collectd plugin and change zk file name

[wasfree]

Hi,

This merge will:
1. Add new collectd plugin perl to this formula 2. Fix filename for zookeeper plugin from zookeeper.conf in zookeeper.sls 3. give the java plugin the ability to set an prefix. InstancePrefix prefix https://collectd.org/documentation/manpages/collectd-java.5.shtml