BMP-2. Creates bento-maven-plugin to run the Docker-ized bento-cluster.

Consolidate hbase-maven-plugin into bento-maven-plugin. This plugin runs bento-cluster in a Docker container for integration testing in a Maven build. Uses the image from the 'docker' branch of bento-cluster.

issue: https://jira.kiji.org/browse/BMP-2
review: https://review.kiji.org/r/2125