Access level check

[TatevikGr]

Summary

• PermissionChecker to check ownership and Privileges

Unit test

• PermissionCheckerTest

Code style

Have you checked that you code is well-documented and follows the PSR-2 coding
style?

You can check for this using this command:

vendor/bin/phpcs --standard=PSR2 src/ tests/

Other Information

If there's anything else that's important and relevant to your pull
request, mention that information here. This could include benchmarks,
or other information.

If you are updating any of the CHANGELOG files or are asked to update the
CHANGELOG files by reviewers, please add the CHANGELOG entry at the top of the file.

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