[Refugees and migrants make their way at the municipality-run camp of Kara Tepe on the island of Lesbos]By Karolina Tagaris LESBOS, Greece (Reuters) - The flow of new arrivals has slowed to a trickle, but thousands of migrants remain in limbo on Greece's islands, in grim camps they liken to prisons. Seven months since the European Union and Turkey signed a deal to shut off the route taken by a million people last year, boats now rarely arrive on Lesbos, once at the centre of the human tide. A fire swept through part of Moria camp, a disused hilltop military base, after a protest in September, forcing thousands to flee.