‘The Legend of Tarzan" focuses on the life of the "ape man" eight years after he returned to stately Greystoke Manor in England, along with his wife, Jane, and tells of the situation that brings them back to the thrills, dangers and romance of Africa.Here’s a prediction: After seeing the film, which opens in Boston on Friday, no one will have anything but huzzahs concerning the casting choice of 39-year-old Alexander Skarsgård as the iconic character.