PARIS (AP) - The spotlight shines more brightly each day on Nicolas Sarkozy, France's rising political star, who has picked a very public sparring match with President Jacques Chirac. The focus on Sarkozy sharpened further Friday with the resignation of the chairman of the ruling Union for a Popular Movement - a job the ambitious finance minister sees as his stepping stone to the French presidency. As finance minister since April, Sarkozy has challenged Chirac with growing frequency on issues ranging from defense spending to labor market reform - a trend that prompted Chirac to use a television interview Wednesday...