Added support for optimalized relations loading.

[Unlink]

Pridaná podpora pre naťahovanie relácii.
Príklad, DDL a triedy Post a User: https://gist.github.com/Unlink/d74fb61fa8bb1e971f84406a358a0cb1

$posts = Post::getAll();
foreach ($posts as $post) {
    echo $post->getOneRelated(User::class)->getFullName();
}

        
$users = User::getAll();
foreach ($users as $user) {
    echo count($user->getAllRelated(Post::class, where: "visibility = 'public'"));
}