Added 'rich' Python package for logging handling

Fixes #4

[x] Refactored logging logic
[x] Use rich package for logging handling
[x] Use rich-argparse to enable rich formatting for help/description.
[x] Created cli.py for CLI entry point (moved from __init__.py)
[x] Added --poor/--nocolors global option to disable rich functionality and show output with no styling/colouring.
[x] Created rich_amami.py to include all settings related to rich and rich-argparse.

ACCESS-NRI / amami