Update Text-to-CAD tutorial

[greg-kcio]

I made a few updates to the Text-to-CAD Python tutorial. Functionally it's the same.

• Removed the term ML-ephant because the Python package is still called kittycad so I think this is less confusing
• Added instruction to install the kittycad Python package
• Updated the Python code to be more idiomatic for a script: removed type hints and raise statements, made the code more concise
• Added a note about which file formats are returned
• Added a note about prompt complexity influencing processing time
• Use STEP instead of GLTF format

Merge with KittyCAD/litterbox#199

[jgomez720]

Looks good to me. I like the changes.