A new joint venture between strange bedfellows — the New York Yankees and the Dallas Cowboys — had its roots right here in Tampa. The baseball and football sports franchises on Monday said they formed a company to handle all of the concessions, catering and retail merchandising at each team's new $1-billion stadiums. The company, called Legends Hospitality Management, was created by the Yankees last year to handle food and beverage stands at their training facility in Tampa — the former Legends Field, now called Steinbrenner Field. A Goldman Sachs executive working with the Yankees brought the idea to the Cowboys to create the joint business venture. Goldman Sachs is also part owner of the Yankee's YES cable TV network.