tutorials, code modularization

[mjstrumillo]

Congratulations on scGPT release! Clearly this is great research however I have real trouble following the tutorials eg. Fine-tuning on Pre-trained Model for Cell-type Annotation on datasets other than provided - are you planning further code modularization? Many users would benefit from clearer explained tutorials and slightly rewrote code (even if just for the tutorials). Do you take suggestions on this?