Nicolas Economou | Nurphoto | Getty ImagesBitcoin slid to its lowest level since in more than two months to kick off May, as investors kept an eye on the Federal Reserve's upcoming interest rate decision.The cryptocurrency dropped as much as 7% to $56,526.00, its lowest level since Feb. 27, according to CoinMetrics. It was last lower by about 4.5% at $57,037.42.Bitcoin has been trading in a tight range, with key catalysts for the cryptocurrency — U.S. exchange traded funds and the halving — now behind it. Its retreat from March...