Document which files/snippets for which tools

[oliverklee]

Goal

I as a user want to have an overview which files/snippets are relevant for which tools

Acceptance Criteria

• [ ] the relevant informations are documented

Additional Information

It can be a bit overwhelming for new users of this extension if they want to use only a subset of the tools.

So we should document which files/snippets are relevant for which tools.

[oliverklee]

Also explain the strategy/approach for PHPStan (baseline, levels etc.).

[josefglatz]

That would be very helpful!

[DanielSiepmann]

We also should cover the purpose and benefits of each tool. That allows new users to decide which tools they wanna use first.