Commands can now specify a command-line arg spec to enable automatic argument parsing and improved help text.
New commands should use this arg spec format and existing commands can be updated if desired.

* Adds tools.cli command parsing and improved option behavior for v2 export and load
* Fixes --no-collections export, empty settings export
* Improves command error handling, adds help text on error
* Lists valid commands when unknown command is given
* Cleans up collection selection for generic export
* Supports --user by email in serdes v2 export