Refactor Author configuration

[caendesilva]

A nice way to define authors would be with a helper facade in the config. Here's an example idea:

'authors' => [
    new Author([
        'username' => 'mr_hyde',
        'name' => 'Mr Hyde',
        'website' => 'hydephp.com',
    ]),
    
    new Author([
        'username' => 'ms_hyde',
        'name' => 'Miss Hyde',
    ]),
];

This has the added benefit of ensuring all Authors have a username as the schema will be right in the config which I really like.

Originally posted by @caendesilva in #442 (comment)