WHO ARE the happiest music executives in the land these days? The big guys at Warner Records. All who have heard Madonna's coming CD, "Confessions on a Dance Floor," have been blown away. (Including WR's movie - star handsome CEO Tom Whalley.) "Confessions" is entirely a dance - driven pop disc. No message. No ballads. All fun. These days M seems serene as the chatelaine of an English manor, feeding the chickens, riding, tending to her children, etc. (She, her home and her kids are gorgeous in Vogue for August.)

 But the once - shocking icon can still get into the groove. And she wants her fans to know it. The album hits stores in November.