Brandon Nimmo went first. Then it was Edwin Díaz and Pete Alonso on back-to-back days at baseball’s winter meetings. Three fan favorites headed out the door in 2 1/2 weeks — a powerful gut punch to angry New York Mets fans wondering what on earth the front office is thinking. As the club embarks on a major makeover, suffice to say owner Steve Cohen and president of baseball operations David Stearns are not the most popular couple in Queens right now. Stearns says there is work to do, but there are many good players available and he’s confident the Mets will like their team when opening day arrives.