Feature/kafka guide app

Initial commit of Kafka Ingestion Guide. This is specifically for Kafka Cluster version 0.8.x.
In order to utilize the \`KafkaSubFlowlet\`, a Kafka Zookeeper connection string along with 
a Kafka Topic must be provided as runtime arguments. You can provide these to the \`KafkaSubFlowlet\` as 
runtime arguments of the \`KafkaIngestionFlow\`. The keys of these runtime arguments are: