A NEW NET POWERHOUSE? - Talk about an October surprise. Staid, 165-year-old media conglomerate Bertelsmann makes a deal with the Devil: Musicdownloading, file-sharing, upstart renegade Napster. Why? Bertelsmann chief Thomas Middelhoff envisions a future when all of his company's content will be digitalized and downloadable for a fee-using Napster software. But the deal is fraught with risk