Refactor for using Drupal core instead of variationcache

This module is now part of core and VC had a release that should work with both D10.2 and below

It was still breaking my site when I updated to D10.2 even after updating variationcache to latest (1.5), doing drush updatedb and drush cr. With errors expecting type \Drupal\variationcache\Cache\VariationCacheInterface but getting \Drupal\Core\Cache\VariationCache in flexible_permissions/src/ChainPermissionCalculator.php line 63.

I ended up making some small modifications to a copy of the flexible_permissions module to use the new Core variation cache instead of the variationcache module. I am not 100% certain I got everything right, but my modified code is working for me.

@Ruslan-Piskarov - If you want to try it out, it's at https://github.com/leeksoup/flexible_permissions on the use-core-variationcache branch.

@kristiaanvandeneynde even though this module is compatible with the core variation cache the composer.json has a dependency "drupal/variationcache": "^1.0" which prevents removing the contrib variation cache module. I have submitted a small patch to remove the dependency.

This module still requires VariationCache because we're using those namespaces. We can't change them without it being a BC break. So for now there is nothing to fix. As mentioned in #4 VC had a release that uses core's classes if you're on D10.2

Please stop reopening this issue and especially with patches that have nothing to do with the issue at all. You've posted a patch for core's SystemAdminMenuBlockAccessCheck

Apologies, i submitted a wrong patch. I wanted to submit a patch just to remove composer dependency which was preventing contrib variation cache to be removed from the project. Il be more careful henceforth. thanks

Yeah no worries. I know I wrote in the VC release notes that you can remove the module once you checked the namespaces in your own code, but with contributed modules it's not as easy as we have to maintain BC.