Add RouteKeyMethodToRouteKeyAttributeRector

[MrPunyapal]

This PR adds a rule to apply the new RouteKey rule.

Example.

 use Illuminate\Database\Eloquent\Model;

+#[\Illuminate\Database\Eloquent\Attributes\RouteKey('slug')]
 class Post extends Model
 {
-    public function getRouteKeyName(): string
-    {
-        return 'slug';
-    }
 }