Refactored code to use PHP8 attributes instead of annotations

In this change, Doctrine and validation annotations have been replaced with PHP8 Attributes. The Rector tool has been configured with a list of annotations to convert to attributes. As a consequence, the PHPStan's rules have been updated to reflect these changes. The PHP8's nullable operator (?) has been added where required, and comments in field declaration have been replaced with #[Attribute] syntax.

src/Bundle/ChillCustomFieldsBundle/Entity/CustomFieldsGroup.php

@@ -13,7 +13,6 @@ namespace Chill\CustomFieldsBundle\Entity;
 
 use Doctrine\Common\Collections\ArrayCollection;
 use Doctrine\Common\Collections\Collection;
-use Doctrine\Common\Collections\Order;
 use Doctrine\ORM\Mapping as ORM;
 
 /**
@@ -36,7 +35,7 @@ class CustomFieldsGroup
      * @var Collection<CustomField>
      */
     #[ORM\OneToMany(targetEntity: CustomField::class, mappedBy: 'customFieldGroup')]
-    #[ORM\OrderBy(['ordering' => 'ASC'])]
+    #[ORM\OrderBy(['ordering' => \Doctrine\Common\Collections\Criteria::ASC])]
     private Collection $customFields;
 
     #[ORM\Column(type: \Doctrine\DBAL\Types\Types::STRING, length: 255)]