LOS ANGELES — Former NFL star Darren Sharper removed all doubt Monday that he drugged and raped women, taking the first of several legal steps to own up to sex assaults in four states that will send him to federal prison for about nine years. In two separate cases, Sharper pleaded guilty to sexual assault in Arizona and no contest in California to raping two women he knocked out with a potent sedative mixed with booze. Sharper, 39, wearing a striped, light blue suit, said it was in his best interest to enter …