Add CLI commands to the package

[andredelft]

Hi!

Thanks for this great package! I use it a lot, and thought it might be helpfull to use it directly from the terminal, to improve my workflow. I therefore created the two terminal commands beta-to-uni and uni-to-beta using click. I have created this PR to share this with you, should you be interested in it as well! Please refer to the added section in the README for instructions.

Best,

André