CHICAGO — The rivalry between the Chicago Cubs and Milwaukee Brewers has been heated over the last seven years, thanks to the proximity of the cities, the fact both teams were usually contenders for the National League Central title and the presence of Willson Contreras. But the Brewers are heavily favored to win the division this season while the Cubs have transitioned since last summer’s sell-off. There were thousands of empty seats at Wrigley Field on Thursday for opening day and even more on a frigid Saturday afternoon that saw the Cubs cruise to a 9-0 win in a chippy game that included a …