Fix custom PageResource not being considered on Pages

[lucasgiovanny]

Currently, if you define a custom Resource on filament-fabricator.php, this resource is not considered on the plugin Create, Edit, List, and View pages.

'page-resource' => \App\Models\PageResource::class,

This PR fixes this matter, adding the method below on every page:

public static function getResource(): string
{
    return config('filament-fabricator.page-resource') ?? static::$resource;
}

[Z3d0X]

Thanks