KANSAS CITY, Mo. — The Royals injected some certainty into the discussion Tuesday when they announced their choice of locations for a new ballpark in downtown Kansas City that they say will be a transformational project connecting some of the city’s key cultural amenities. The 17.3-acre East Crossroads site, with the former Star printing plant its focal point, stretches from Grand Boulevard to Locust Street, and 17th Street to Truman Road. T-Mobile Center is immediately to the north. The Kauffman Center for the Performing Arts and the city’s convention center are nearby, as is the city’s stree…