The term “design hotel” gets thrown around a lot, but rarely is it applied to a century-old building whose interiors seem to have crystallized sometime around 1955. Copenhagen’s Hotel Alexandra is a time capsule; it’s as if someone fed the pages of a textbook on original mid-century Danish design into a 3-D printer and out popped its guest rooms, culminating in a series of thoroughly realized homages to several of the great Danish furniture designers.