Manchester City and Arsenal will have the chance to lay down an early marker when they meet in the English football’s season opener – the Community Shield at Wembley Stadium on Sunday. Pep Guardiola’s side ended last season in a celebratory mood after winning the Premier League, FA Cup and Champions League. The Gunners were their nearest challengers in the English top flight, but were overhauled on the run-in as Man City powered clear. City are bidding to win the…