Added kafka_install method

Added a new method and install type for Kafka installation. kafka installation requires Zookeeper to be setup and running before Kafka server can be installed/configured. The new method first installs the Zookeeper nodes and then moves on to installing Kafka Server nodes.
Probably good form to add a `sleep(0.5)` here to prevent us from driving the Chef server load high, should `knife search` run quickly.