Who is Leslie Moore from Anne's House of Dreams and what is their importance?

When Anne first arrived in Four Winds Harbor, she saw a girl on the side of the road herding geese. She was by far the most beautiful girl Anne had ever seen, and she is described as having the most perfect face, as well as golden blond hair that gleamed in the sunlight. Later, Anne meets the girl on the beach and learns that she is a neighbor, Leslie Moore, who lives just up the pathway.