Replace PHP-CS-Fixer and Rector with Mago Linter & Formatter

[norberttech]

Describe the Proposal

As a firs step we should try to replace CSFixer (coding standards) and Rector (mostly unused imports) with Mago Linter & Mago Formatter which seems to be stable enough already.

API Adjustments

No adjustments needed

Are you intenting to also work on proposed change?

None

Are you interested in sponsoring this change?

None

Integration & Dependencies

No response