Buoyed by the Oscar nomination of Chile’s very own Maite Alberdi for her poignant doc, “The Eternal Memory,” Chile’s documentary sector could not be more vibrant. Debuting at the Berlinale’s Forum sidebar is “Oasis,” the latest feature doc from the Mapa Fílmico de un País (MAFI) collective and the hybrid LGBTIQ+ themed short film “Towards …