Add Perplexity API

This feature is very much linked to the fact checking feature request. I know the founder of Perplexity (I photographed his wedding lol). And he told me how they produce up to date, fact backed answers in an efficient and parsimonious way compared to Google. Whenever I need facts to add authority to an article Perplexity is an easy choice. Bezos and Karpathy apparently agree.

Interesting, might look at their pricing.