[A migrant woman makes her way next to tents set at the old baseball venue of the former Hellenikon Olympic complex, which is used as a shelter for refugees and migrants, in Athens]By Angeliki Koutantou and Karolina Tagaris ATHENS (Reuters) - A crumbling former Athens airport complex housing thousands of stranded migrants will be transformed into one of Europe's biggest coastal resorts if a Greek development company realises its ambitions. The 7-billion-euro plan to develop Hellenikon, a site three times the size of Monaco, has the potential to help kick-start an economy that is limping back to growth after seven years of recession.