Enable TLS by default and add UI for client/daemon auth

Turns on TLS by default and uses public keys to authenticate access.

- This PR still may require further testing and input on the user experience.
- FSNotify support has not been added to detect changes to authorized_keys
- Implementation of proposal from #7667

@bfirsh please review and comment on whether this is missing anything needed
https://github.com/docker/docker/pull/8265/files#r19660996 also means we get to clean up this so it makes more sense.