If Dickens had lived to write about the Jazz Age, he would have produced a novel much like Kate Atkinson’s “Shrines of Gaiety.” A sprawling and sparkling tale set in London in 1926, Atkinson’s latest is overrun with flappers, gangsters, shilling-a-dance girls, disillusioned veterans of the Great War, crooked coppers, a serial killer, absinthe cocktails, teenage runaways, snazzy roadsters and a bevy of Bright Young Things.