Feature/improve vcl hash

[toonvd]

Description

This PR is a rework of the Magento VCL (the vcl_hash part) PR found here: https://github.com/magento/magento2/pull/36796/files

It is mildly adapted since I decided to not remove the hashing on the graphql part.

PRs for other subroutines will follow (probably weekly)

All credits go to @peterjaap and @ThijsFeryn, I am simpling slicing this up and removing controversial parts to get early approval.

Related Pull Requests

https://github.com/mage-os/mageos-magento2/pull/62

Manual testing scenarios

• Load the new VCL
• Test if Graphql behaves the same way when authenticated and not authenticated (storeswitch / currencyswitch)

Contribution checklist (*)

• [x] Pull request has a meaningful description of its purpose
• [x] All commits are accompanied by meaningful commit messages
• [x] All new or changed code is covered with unit/integration tests (if applicable)
• [x] README.md files for modified modules are updated and included in the pull request if any README.md predefined sections require an update
• [x] All automated tests passed successfully (all builds are green)