As the magical creatures of Middle Earth prepare to resume venturing through Auckland, New Zealand, for Amazon’s “Lord of the Rings” prequel series, the mythical world of Pandora has been bursting into life for James Cameron’s “Avatar” sequels in Wellington, just one hour’s flight south. Meanwhile, on the South Island, stars like Viggo Mortensen are planning to embark on “The Greatest Beer Run Ever” in Dunedin, while a game-changing production studio has been proposed for Christchurch.