O2.1: Make it easier for humans & harder for censors to get bridges from moat distributor.

Moat is a tool used inside Tor Browser for users to request bridges when Tor is censored. Moat uses CAPTCHAs in an attempt to prevent censors from using bots to obtain too many bridge IP addresses. The current CAPTCHA solution is too easy for bots and too difficult for many people, particularly non-English native speakers, to solve. In this Activity, we will implement a different CAPTCHA solution that is harder for bots and easier for humans.