offline

Previously IDs of container images were gotten from tar files of container
images but that way was wrong. If multiple json files are contained in a
tar file, the script got multiple IDs and tried to pass these IDs on
`docker tag` command. Then the command was failed.

This updates the script to get image IDs from `docker image inspect` command
to fix this issue.
In addition, this adds a check a registry container exists already or not
before deploying registry container to avoid a container conflict failure.