MIAMI — The passport — the key to being able to travel — has power. But not all passports are equal. Some open more doors than others to travel around the world. The most powerful passports are those that offer greater freedom to enter the most countries without additional entry requirements such as visas. Every year the list of the most powerful passports in the world is released. Different factors affect the freedom to travel and the strength of a passport. More than 100 countries participate in this sort of global competition, a classification based on data from the International Air Transp…