Add AuthConfig.

All of these items are Serializable.

Signed-off-by: Nigel Magnay <nigel.magnay@gmail.com>
More serializable improvements.

More commands.

Remove tag from pushImageOnRegistry. Seems to be an undocumented /
deprecated feature, but it breaks pushing to registries as the tags
don't follow.

Signed-off-by: Nigel Magnay <nigel.magnay@gmail.com>