Automatic merge from submit-queue
Kubelet: add --container-runtime-endpoint and --image-service-endpoint
Flag `--container-runtime-endpoint` (overrides `--container-runtime`) is introduced to identify the unix socket file of the remote runtime service. And flag `--image-service-endpoint` is introduced to identify the unix socket file of the image service.
This PR is part of #28789 Milestone 0.
CC @yujuhong @Random-Liu