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.
When running the script, I faced the following error but it was
difficult to know the root problem due to lack of error handling.
docker tag" requires exactly 2 arguments.
See 'docker tag --help'.
Usage: docker tag SOURCE_IMAGE[:TAG] TARGET_IMAGE[:TAG]
Create a tag TARGET_IMAGE that refers to SOURCE_IMAGE
To investigate such errors easily, this adds an error handling.
