Allow non-Zwift users to watch when I ride

As a user, I want Zwift to generate a link and post to Facebook (or other social media) where my non-Zwifter friends can join as a guest and watch me do a ride. Bonus points if their comments on the Facebook post show up on my feed while I’m riding.

Promotes the game to non-Zwifters. Allows them to experience the game than just some random YouTube video.