Automatic merge from submit-queue
Kubelet: Refactor all but image related functions in DockerInterface
For #23563.
Based on #23699 and #23844.
Only last 3 commits are new. This PR refactored all functions except image related functions, including:
* CreateExec
* StartExec
* InspectExec
* AttachToContainer
* Logs
* Info
* Version
@kubernetes/sig-node