Tracking Issue: complete the CLI `store` MVP

[alilleybrinker]

Right now we have partially implemented support for working with Artifact Input Manifests in the CLI, but we need to complete it. This really just means adding initial support for the remaining "missing" commands, namely:

• Implement store get in the CLI #198
• Implement store list in CLI #197
• Implement store remove in CLI #196
• Implement store add in CLI #195

[alilleybrinker]

Done! There's more work to do in the CLI, but the store subcommand MVP is now done.