With a painted white face and head, wearing an all-white ensemble save for long black gloves and gigantic black platform stiletto boots, Gena Marvin teeters as she balances on snow-covered rocks. She poses for a photograph, the sea rippling gently in the background behind her contorted figure, frozen still in the arctic chill. It’s a striking scene that opens the new documentary “Queendom,” which follows the queer Russian performance artist as she creates artwork that challenges societal expectations and political situations — and the backlash she faces for it.