Write recruiting copy

[b]

Need to spell out more clearly why a developer would want to join and why a player would sign up.

[b]

Started this here: https://docs.google.com/document/d/1yhJLsGNt1rbr2qs5sQrAhs7dt84iwSyoaC8Za3nKfj4/edit#heading=h.bpz35ga9kqly