Add repository list-paths and repository move-paths

Summary: Ref T7149. These formalize the local path adjustment step for cluster imports, rather than relying on an ad-hoc script.

Test Plan: Used list-paths and move-paths to list and move repositories.

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: epriestley

Maniphest Tasks: T7149

Differential Revision: https://secure.phabricator.com/D13621