Changes included:
- Ingress network should not be attachable
- [manager/state] Add fernet as an option for raft encryption
- Log GRPC server errors
- Log leadership changes at manager level
- [state/raft] Increase raft ElectionTick to 10xHeartbeatTick
- Remove the containerd executor
- agent: backoff session when no remotes are available
- [ca/manager] Remove root CA key encryption support entirely
- Fix agent logging race (fixes https://github.com/docker/swarmkit/issues/2576)
- Adding logic to restore networks in order
Also adds github.com/fernet/fernet-go as a new dependency
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>