By Jorge Otaola and Eliana Raszewski BUENOS AIRES (Reuters) – The abrupt departure of Argentina’s economy minister and lack of a clear successor could threaten to further destabilize an economy already shaken by sky-high inflation, rising energy costs and growing fears over possible new defaults on debt. Martin Guzman, the architect of the South American country’s recent $44 billion deal with the International Monetary Fund (IMF), resigned on Saturday as tensions within the government boiled over as to how to handle the economic crisis in one of the world’s top grain producers. A relative mode…