Ability to create a listing from a list of items and specifying a callback to find the order of the items

[khalyomede]

For example instead of this:

use Khalyomede\ReorderBeforeAfter\Listing;
use App\Models\Product;

$items = Product::all()->map(fn (Product $product): Item => new Item($product, $product->order));
$listing = Listing::from($items);

We could have this, which is reducing the redunduncy if the list of objects comes from a previous call:

use Khalyomede\ReorderBeforeAfter\Listing;
use App\Models\Product;

$listing = Listing::outOf(Product::all(), fn (Product $product): Item => new Item($product, $product->order);