Story 1840. Updated approve command based on the new UserPersistence interface. Added unit tests. Refactored some codes.

Story 1840. Added support for all commands. Refactored code to promote code reuse. The commands have not been end-to-end tested because required credentials and ACI's needed to execute these commands (except for --list) are not in place.

Story 1840. Initial setup of this module with the command line framework. The 'List' command appears to work.