Adopt ekino/phpstan-banned-code and use it to prevent further usage of uniqid(), md5(), sha1()

Problem/Motivation

It's being discussed in the parent to replace calls to uniqid() with something else. If that's done, it would later be rather convenient to prevent it being readded by mistake.

In #2972100-17: Remove usage of uniqid it was introduced https://github.com/ekino/phpstan-banned-code as a potential PHPStan based solution.

Proposed resolution

Experiment and if it's worth adopt the PHPStan extension.

Remaining tasks

User interface changes

API changes

Data model changes

Release notes snippet