From Billy Joel to Gilda Radner, Diane von Furstenberg to Jennifer Lopez, the annual festival often opens with a star-centric doc. This year, Earth, Wind & Fire joins the party. As is now seeming tradition, this year’s Tribeca Festival ( its milestone 25th! ) will open with the premiere of a star-studded new documentary about entertainment royalty. From Billy Joel to Gilda Radner , Diane von Furstenberg to Jennifer Lopez , the annual festival often opens with a star-centric doc, and this year,