Ka-ching! Wednesday's Powerball jackpot soared to $1.5 billion as get-rich-quick mania seized America this week. But you don't need to wait for the drawing to know who'll score the royal payoff. The biggest winner of the multi-state numbers game is — drum roll, please — Uncle Sam. Powerball is a government-sponsored gambling racket in 44 states, plus Washington, D.C., Puerto…