Map community ratings board

Every map players have rated, with what they think of it. overallBayes is the mean shrunk towards the average of every map vote and is what the board sorts on, so a map three people liked cannot sit above one four hundred have judged. The prior is taken over the map votes alone rather than over every community vote on the site, because the two populations sit at different heights: people are far harder on the ground they are sent to than on the vehicles they chose to buy. Maps nobody has rated are absent rather than returned with nulls, so an unrated map is never read as a badly rated one. There is no over/underrated column here, unlike the vehicle board: it compares a reputation to a measured win rate, and no per-arena win rate exists anywhere. The votes are global, the identities are the region's catalogue.