By Stephen Culp NEW YORK (Reuters) – U.S. stocks advanced on Monday, extending last week’s gains as signs of economic softness suggested the effects of the Fed’s aggressive policy aimed at cooling the economy, thereby curbing decades-high inflation, are beginning to take root. All three major U.S. stock indexes gained momentum throughout the first session of a week jam-packed with high profile corporate earnings and crucial economic data. A report from S&P Global showed a contraction in business activity this month, offering a hint that the Federal Reserve’s barrage of steep interest rate hike…