Changed module names to lower-case and group to org.opencadc to conform to maven repo naming standards

Story 1840. Since approvePendingUser() returns the approved user, added code to print details of the approved user.

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.