This adds support for private docker registries, by adding
an optional `registryAuth` field in the CreateFunctionRequest.
Auth must be passed as base64-encoded basic auth, similar to
how done in Docker file store credentials (~/.docker/config.json).
Credentials are then passed to swarm at service creation.
* Service lookup
* Disable KeepAlive to force RR for replias.
* set KeepAlive to 0
* Remove temporary file
* Support white and rename function
* Remove debug from node sample