GLPI11 Compatibility

[MyvTsv]

Checklist before requesting a review

Please delete options that are not relevant.

• I have performed a self-review of my code.
• I have added tests (when available) that prove my fix is effective or that my feature works.
• I have updated the CHANGELOG with a short functional description of the fix or new feature.
• This change requires a documentation update.

[Rom1-B]

Please add phpstan-glpi:
composer require --dev glpi-project/phpstan-glpi

And update config file phpstan.neon

[Rom1-B]

You need to redo the PR from the repo, without going through your fork, otherwise we won't be able to create the tag for the beta version.