PredictionIO + Universal Recommender as a Docker container

Include only spark. Connect to remote mysql and elasticsearch

Set environment when running docker (used by files/pio-env.sh): MYSQL_JDBC MYSQL_USER MYSQL_PASS ELASTICSEARCH_HOST ELASTICSEARCH_PORT

PredictionIO build with: ./make-distribution.sh -Dscala.version=2.11.11 -Dspark.version=2.1.1 -Delasticsearch.version=5.5.2