By Tzvi Machlin Global soccer giant Real Madrid made history over the weekend by winning their 14th Champions League title. But they could make even more history this summer by bringing a United States player into the fold. According to soccer insider Fabrizio Romano, Real Madrid are preparing a bid for American goalkeeper Gabriel Slonina. The 18-year-old goalkeeper plays for Major League Soccer’s Chicago Fire and he has five clean sheets in 14 games – tied for fifth-most in the league. If signed, Slonina would be the American to ever be signed to the Real Madrid first team. Only one American …