Add FAQ page

[milesfrain]

Update: Unofficial FAQ

As discussed in #217, maybe this repo is not the place for an FAQ, but I think one should still exist somewhere.

It seem that #217 was shutdown due to overlap with the Differences from Haskell article. The FAQ could still list the question and then link to a section of a particular guide that contains a more detailed answer.

Examples of FAQs for other languages:

• ReasonML
• Rust
• Elm
• ClojureScript and Clojure
• TypeScript
• Haskell