You probably first saw Christopher Kimball as the bow-tie-and-glasses-wearing, endlessly curious host of “America’s Test Kitchen,” the show he helped create back in the early 2000s. Now, he’d like to reintroduce himself, this time with a broader cooking philosophy, and he’s coming to Colorado to share it with you. Kimball’s new venture is called Milk Street, and like ATK, which sprang from Cook’s Illustrated magazine, it spans a variety of media.