Champion Difficulty Easy Overhaul

I think champion difficulty could use some work to better reflect reality.

Difficulty should be linked to the difference between high level and low level of play. For example, Ryze is listed as difficulty 2, but it really should be 3 (or 4 if a new level is added) given that he is really difficult to do well except at high elo and pro play.

Right now, I think the difficulty reflects how hard it is to win vs bots or something.