1. Multi-stage build with an extensive cleanup of useless files and optional image compression
2. Start three-node etcd cluster
3. Start three-node Patroni cluster
4. One container with haproxy
5. All container names are prefixed with "demo-" and don't have suffixes
6. Decommission dev_patroni_cluster.sh script, docker-compose is now standard de-facto.
7. Provide more examples in the docker/README.md