Implementing TLS for Swarm Cluster

[sebinjohn]

This issue can be used as a place to discuss the steps we need to take towards implementing TLS for docker swarm.

The primary reading material for this is the official documentation https://docs.docker.com/swarm/configure-tls/

Please add if any better readings are available.

[sebinjohn]

May be we can somehow reuse this? https://github.com/ansible/role-secure-docker-daemon