The Braves on Monday acquired first baseman Matt Olson from the Oakland Athletics for outfielder Cristian Pache, catcher Shea Langeliers, and righties Ryan Cusick and Joey Estes. This trade made something all but official: The Freddie Freeman era in Atlanta is over. Olson, who is a free agent after next season, is a slugger who is one of the game’s best first basemen. He’s hit .252 with an .859 OPS and 142 home runs over his career. Freeman likely ends his Braves career with a .295 batting average, .893 OPS, 271 home runs and 941 RBIs. Olson reacted to the news, speaking to reporters in A’s sp…