Added library method to search and return ZK nodes for Kafka installatio...

The proposed change will add a new library method that searches "run_lilst:", "roles:" and "recipes:" for ZK nodes and returns them for setting up a Zookeeper / Kafka cluster. The "sleep(30)" is added to let chef-server update the solr index before a search is performed. The unexpected results are returned while performing a search if "sleep(30)" is removed.