[CLI] Add `mv` command to volumes

[Eli Mernit]

Is your feature request related to a problem?

No.

Describe the solution you'd like

It would be nice to move files around volumes using a mv CLI command. For example:

beta9 volume mv ./file.txt ./artifacts/text-files/file.txt

beta9 volume mv [SOURCE-PATH] [DESTINATION-PATH]

Describe alternatives you've considered

Additional context

Thank you for the feature request –- we really appreciate your insight.

[jsun-m]

#265