By Tom Beattie Manchester City-bound teenage prodigy Cavan Sullivan has opened up about his ambition to play for the United States, despite interest from Germany. Already the fifth-youngest player to sign a professional contract with an MLS club, he’s also heading to the Premier League when he turns 18 having agreed a move to Manchester City. The 14-year-old has recently inked a deal with Philadelphia Union on a homegrown contract, indicating his intention to further his skills on home soil before his City move, but he has been hailed as one of the most promising teenage players on the planet,…