So, you’ve always wanted to make your fortune replicating Aunt Sally’s rhubarb shortcake. But the board of health might not okay your kitchen, given the dogs that sleep in the corners and the cats that trespass on counters. Due to the farm-to-table movement and the culinary artisans it has bred, a clutch of kitchens have sprouted up in East Hampton Town to provide a springboard for food entrepreneurs.