Feature request: add percentage column in maps section detailing the play rates normalized by map availability

[davidlenz]

Arabia, Blackforest and Arena are always in the map pool, thus leading to c.p. higher play rates compared to maps not always in the map pool.

One way to realize this could be to mulitply the rates by an availabilty factor. Availability factor could be calculated as number of total days of AOE:DE divided by number of days a map was in the mappool. Thus the factor would range from 0.x to 1, where a 1 would indicate always available, while lower values indicate that the map has not been available all the time.