The wait is over, pitches. The trailer for “Pitch Perfect 3” is here and by the looks of it, the new installment in the a cappella franchise is action-packed. (What is this, “Mission: Impossible”?) After the Barden Bellas graduate college, they struggle to find a place in the real world. That’s when they decide to reunite and hit the road on the USO tour in Europe to prove they still got it.