Add section on paid features

[BekahHW]

I'm not sure where this goes right now, but we need to add two things to docs:

1. What are OpenSauced paid features?
2. Why would you want to use paid features?

Right now, I think FAQs would be a good place for these questions, but I need to think about it.

[BekahHW]

I also might be worth adding the the guides a separate doc on what the paid features do. Or we can include them in the docs and add a label or something like this

[BekahHW]

#262 (comment)