Mexico’s government is preparing to sell a giant parcel of land that could turn an undeveloped area of Mexico City into one of the most lucrative real estate developments in Latin America with a price tag experts see reaching as high as $1 billion. Nearly four times the size of Disneyland at 310 acres (125 hectares), the military site is one of the last big swaths of developable land in central Mexico City, a megalopolis with more than 20 million…