/// Domain Name Extractor
///
/// Given a URL as a string, parse out just the domain name and return it. Uses only the .split() built-in function without regex or urlparse.
///
/// # Examples
///
/// Basic usage:
/// ```
/// let result = algorithmz::string::domain_name("https://github.com/SaadBenn");
/// assert_eq!(result, String::from("github"));
/// ```