MIAMI — The former clinic owner accused of selling performance-enhancing drugs to Alex Rodriguez has agreed to plead guilty in what prosecutors called a wide-ranging conspiracy to distribute steroids to both major league ballplayers and high school athletes. The charges filed Tuesday against former Biogenesis of America owner Anthony Bosch and six others marked one of the biggest salvos yet in a case that has dragged on for nearly two years. The case has sparked lawsuits, mudslinging and suspensions against numerous major leaguers, including Rodriguez.