Group config entries together

[rbruhn]

Inside the config file, there are related configurations that can be grouped together in arrays and referenced using dots in the code. It would be neater to move related items into arrays and reference them accordingly in the code. Also, changing all Notes From Nature references to Zooniverse.

'api' => [
    'domain'  => env('API_DOMAIN'),
    'url'     => env('API_URL'),
    'version' => env('API_VERSION'),
    'token'   => env('API_TOKEN'),
],

config('config.api.domain');