Brian Steinberg Senior TV EditorESPN, which has seen some of its top executives charged with overseeing documentary and investigative work depart in recent months, said it had named news veteran Marsha Cooke as vice president and executive producer of its ESPN Films unit as well as its venerable “30 for 30” documentary unit.Cooke, who spent 24 years at CBS News, was most recently senior vice president of global news and special projects at Vice Media Group.“Marsha’s extensive production