Created Elasticsearch skeleton, need to add Oracle JRE or OpenJDK.
Created centos 7 elasticsearch repo Dockerfile to be used by elasticsearch and logstash builds.
Updated elasticsearch Dockerfile to use repo image and yum install it.
Created centos 7 nginx Dockerfile.
Created Oracle JRE 8 Dockerfile.
Created centos 7 logstash Dockerfile.
Created centos 7 kibana Dockerfile.
Created logstash-forwarder Dockerfile.