Option to configure filenames

[bernhardh]

If you upload an image, the image keeps it original filename like "Fotolia-1224234.jpg". To prevent this, spatie allows to modify the filename with setFilename.

At the moment, there is no way to do this with this package. It would be great, to provide a way, to modify the filename, for example with a callback function. Something like this:

Images::make('Hauptbild', 'main')
    ->setFileName(function($originalFilename, $extension, $model){
        return md5($originalFilename) . "." . $extension;
    });
    
Images::make('Hauptbild', 'main')
    ->setFileName(function($originalFilename, $extension, $model){
        return str_slug($model->name) . "." . $extension;
    });

[bernhardh]

See pull request

[ebess]

merged #14