Needs to improve swarm cluster security

[deniojunior]

• Add network config to restric ports and access to the cluster.
  https://www.bretfisher.com/docker-swarm-firewall-ports/

• Remove necessity of a key-pair to nodes communicate each other. It has to happen throught internal IP. Needs to config VPC.

Project: https://github.com/deniojunior/devops/tree/master/swarm-cluster-aws-terraform