Add a rating filter to Arena

[Ceaseless]

Filters should check for things a player can lose. Leagues can't be downgraded from and end up being a joke as a result, being closer to participation trophies than skill filters for pairing purposes. An "elite player" could have 100 rating. The bottom of the barrel being in the highest league makes those trying to use league filters to get proper pairings much less effective. Having filters based on your rating, even the one outside Arena, would be much more helpful. Even 300 rating is much more reliable an indicator of skill than Elite League. Alternatively, if you want to keep the filters arena specific, set them for number of points within the Elite League, that way the top of the Arena ladder doesn't get paired with any beginners at the bottom.