Add format option for webp support

[tehnorm]

Feature request

Introduced a format option to request the image in a different format.

Currently, the only value allowed is origin which will force the image to be returned to its original format.
If not provided, we will automatically optimize the image using webp

Describe the solution you'd like

$storage = new StorageFile($url, [
 'Authorization' => 'Bearer ' . $service_key,
], $bucket_id);

$result =  $storage->download(uploadPath, [
      "transform" => [
        "width" => 200,
        "height" => 200,
        "format" => 'origin',
      ],
    ])