Add PHP 8 Attribute generator for supported classes

[Haehnchen]

Provide Entity / Doctrine Doctrine generator for PHP 8 Attributes

/**
 * @ORM\Entity(repositoryClass=CrossFarmRepository::class)
 * @ORM\Table(name="cross_farm")
 */
class CrossFarm {}

Based on "a decision" allow generate Attributes instead of DocBlocks

#[ORM\Entity(repositoryClass: CrossFarmRepository::class)]
#[ORM\Table(name: "cross_farm")]
class CrossFarm {}