Symfony 8 compatibility

[acrobat]

Xml configuration is deprecated in Symfony 7.4 and support is removed in 8.0. Bundles are encouraged to switch to php config files.

I tried starting on the compatibility fixes but the test suite is so large and I'm not able to make all tests pass currently. If you want you can start from my branch and continue the necessary changes from there.

The xml to php conversion is done throught the https://github.com/GromNaN/symfony-config-xml-to-php migration tool

master...acrobat:AliceDataFixtures:symfony8-support

[xabbuh]

I opened #321 to fix the CI

[theofidry]

Closed by #338 which has been released.