Implement auto-complete to display the commands available

This issue implements an auto-completion feature in the rover to simplify the discovery of the commands available

When typing rover the rover would display the rover modes available like
--landingzone --clone --help

When type rover --landingzone it would display the landingzone attributes
-a -launchpad -env --help

Locate the rover CLI entry point and the definitions for its top-level modes and landingzone attributes. Check how command-line input is currently parsed, then verify that tab completion lists the requested modes and attributes, including --help.

Written by the indexing model from the issue text.