Talks to sell a majority stake in OnlyFans are being led by Moelis & Co., the investment bank founded by Wall Street legend Ken Moelis, The Post has learned. Moelis bankers engineered the potential deal for the money-minting smut site – in which San Francisco-based Architect Capital could take a 60% stake in a tie-up that values it at $3.5 billion – after at least one other bank shied away from representing OnlyFans, said a source familiar with the matter.  Moelis – whose 68-year-old,