[image-save-load]: support for stdin/stdout

[saehejkang]

Type of Change

• Bug fix
• New feature
• Breaking change
• Documentation update

Motivation and Context

Closes #559

Testing

• Tested locally
• Added/updated tests
• Added/updated docs

Example Commands with Outputs

Save the docker image to the test.tar file

container image save docker.io/library/nginx:latest > test.tar
⠦ Saving image(s) [3s]

Use the test.tar file to load the image

container image load < test.tar
Loaded images:                  
docker.io/library/nginx:latest