Will it be Jimmy Fallon vs. Stephen Colbert in the new late night network ratings wars? According to several entertainment industry insiders, executives at CBS are hoping that Stephen Colbert will take over as the host of The Late Show when David Letterman retires next year. As Mashable notes, conveniently, Colbert’s Comedy Central contract ends in 2015—around the same time Letterman said that he would be going off the air for good during last week’s retirement announcement. Though the network is reportedly eyeing a few other possible replacements (including Neil Patrick Harris, Jon Stewart and Craig Ferguson), sources close to the network say that Colbert is currently the favorite …