THE PHILADELPHIA mob has again been thrown into turmoil with the arrest of Mafia kingpin Joseph "Uncle Joe" Ligambi, 71. More of the Angelo Bruno style than Crazy Nicky Scarfo, according to the Philadelphia Inquirer, Ligambi was reluctant to use violence because it interferrred with his money making schemes. The arrest Monday could signal the end of his run and further imperil the Philadelphia mob. The gentleman gangster and others were hammered with a 50-count indictment that focuses on racketeering, loan-sharking and gambling. But curiously missing is any semblance of violence, of course there are