Podman needs to be able to add an artifact to its local store.  As such, we will develop a `podman artifact add` command.  See man page for details.

QE ideas:

1. Understand the current artifact store by looking at ~/.local/share/containers/storage/artifacts/blobs/sha256/ and podman artifact ls
2. Add an artifact to the store.  Observe changes and confirm the new artifact is in the store and observed with artifact ls
3. Add an artifact where the name is valid but file name is not (should fail)
4. Add an artifact where the name is a duplicate but the file is not (should fail)
5.