Photo Illustration by Luis G. Rendon/The Daily Beast/GettyMaybe Rudy Giuliani is working on an insanity defense for the day he faces RICO charges down in Georgia, along with Donald Trump and 17 others.He certainly seemed on the way to proving himself nuts last week, when he paid an insulting pittance toward a seven-figure legal debt to his longtime lawyer Robert Costello, after letting people believe he had raked in more than $1 million at a fundraiser.As any sane New York lawyer could have pred