Ability to map feature names

[ahinkle]

This PR adds the ability to map feature names to other names.

This introduces a new method, Feature::enforceNameMap(), which provides a customized string that will get saved to the database. This allows for easy refactoring of class based features and shorter strings in the name column.

Feature::enforceNameMap([
    'admin' => AdministrationFeature::class,
    'old-feature' => NewFeature::class,
]);

[timacdonald]

@ahinkle, I've created a PR to document the existing feature that supports doing this: https://github.com/laravel/docs/pull/9322

[ahinkle]

Thanks! I realized that as soon as I submitted this PR 😆