RESGUARDO BUENAVISTA, Colombia — At the edge of the Colombian Amazon, in an Indigenous village surrounded by oil rigs, the Siona people faced a dilemma.The United Nations Development Program, or U.N.D.P., had just announced a $1.9 million regional aid package. In a village with no running water, intermittent electricity and persistent poverty, any money would mean food and opportunity.But the aid program was part of a partnership between the United Nations agency and GeoPark, the multinational petroleum company.