Add some improvements to llms.py

[nonprofittechy]

I'm noticing extract_fields sometimes get back N/A or None values instead of strings. We can tweak the prompt, but this also helps:

define_fields_from_dict({k: v for k,v in answers.items() if (v is not None) and str(v).lower() != "n/a"})

The GoalSatisficationList is a bit too lazy. We should be able to tweak how aggressive we want to be in getting good responses. It's a big difference if it's a student reflection or a legal document. Check the prompt to see if it can be improved but also we should add a parameter somewhere for custom instructions or just to tune how aggressive it will be.