feat: make name set iterable

[ralflorent]

Makes the name set iterable (i.e., for-of statements).

This is similar to parts with the exception that all name components are returned as Name classes (instead of their natural form - e.g., FirstName or LastName) to maintain certain homogeneity and consistency across each name piece.

This PR also includes changes to support flexible types instead of being forced to import enums (Separator, NameOrder, etc.) to customize the behavior of the name components via Config. For example, working with names ordered by family name should be as easy as doing this:

import namefully from 'namefully';

const barack = namefully('Obama Barack', { orderedBy: 'lastname' });
console.log(barack.initials({ orderedBy: 'firstname' }); // ['B', 'O']