SYDNEY — The Trump Organization has signed a deal to build its first tower in Australia , in a project worth 1.5 billion Australian dollars ($1.06 billion) that developers say will become the country’s tallest building. The 91-story skyscraper is planned for the Gold Coast, a popular seaside destination in the Australian state of Queensland. It will include a “six-star resort-hotel,” 270 apartments, shops, a beach club and a swimming pool, local property developer Altus Property Group said in a