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/ChillMainBundle/Entity/User.php

@@ -111,10 +111,9 @@ class User implements UserInterface, \Stringable, PasswordAuthenticatedUserInter
 
     /**
      * The user's mobile phone number.
-     *
-     * @PhonenumberConstraint()
      */
     #[ORM\Column(type: 'phone_number', nullable: true)]
+    #[PhonenumberConstraint]
     private ?PhoneNumber $phonenumber = null;
 
     /**