For the past 30 years, my goal has been to make documentaries about lesser-known Jewish heroes that counter negative stereotypes. My newest film, "Yoo-Hoo, Mrs. Goldberg," celebrates the accomplished, and long-forgotten, Gertrude Berg, the creator of the domestic sitcom. Gertrude Berg’s radio show, "The Rise of the Goldbergs," debuted in 1929 and was an American…