Switch challenge name source from path to README

[delta6862]

Currently, the challenge name is pulled from the path

def update_or_create_challenge(path, folder=get_challenge_path()):
    # Get information
    category, name, _ = path.split("/", 2)

While fine for most names, it can generate issues and uncertainties with certain characters (the most obvious example being a \).

Instead it would be better to take the formal name from the challenge README (which also has the title)