An Arsenal youngster who Mikel Arteta sold for a nominal fee last summer just scored a hat-trick for his new club in a 5-2 win last night. Arsenal have let plenty of youngsters leave the club in recent years, with Charlie Patino perhaps set to be the next in the summer. Lino Sousa, an inverted full-back that many were excited about, left for Aston Villa in January, and it’s now reported that Patino’s future belongs elsewhere too. If there’s one concern about Arsenal under Mikel Arteta right now, it’s the lack of chances that have been given to young players. Given the sharp upwards trajectory …