[GeneratorBundle] Add support for php8 attributes in generators

[acrobat]

Q	A
Bug fix?	no
New feature?	yes
BC breaks?	no
Deprecations?	no
Fixed tickets

Generate:page and generate:pagepart are not using php8 attributes as they use the Doctrine EntityGenerator (which is deprecated and doesn't support php 8 attributes). We will need to replace them with a maker command where we have move control over the used class templates. Most of the other generated files are updated to support php 8 attributes when they can be used (Symfony constraints/route etc: php8+ and symfony 5.2+ and doctrine mapping type = attribute for entities)