New Orleans’ budding video-game sector is set for a big boost, with one of the industry’s most celebrated entrepreneurs starting a new gaming studio in the city with the promise of 75 local jobs paying an average of $100,000 a year each. There are few bigger names in digital gaming than Jeff Strain, who founded and sold two video-game companies over the last two decades, and who is starting his latest studio — Possibility Space — on Poydras Street in the Central Business District. The move is a coup for economic development agencies GNO Inc. and Louisiana Economic Development, which have courted Strain at his former base in Seattle for…