Major update - added strict types, added code quality tools

[indy2kro]

Major update, modernize tool, contains breaking changes from previous version.

• Dropped support for php versions older than PHP 8.2 (not compatible with all changes)
• Added Rector support
• Added PHPinsights support
• Added PHPstan support
• Updated PHPstan to level 9
• Added strict_types to all files
• Updated github actions to use caching, added more tools execution
• Split class in multiple files to reduce complexity
• Added more tests

[bluemoehre]

Hey @indy2kro , many thanks for your contribution.

As already said in your other PR, it will take some time to be able to check all the changes you squeezed in this single PR. Again, I can just recommend providing smaller PRs, because that helps in getting code merged quickly and efficiently.

[indy2kro]

Well, this one is .. basically a re-write of the app. I understand your request, but the truth is there is so much changed it's easier to just consider a review from scratch or just to keep it as a separate fork.

[bluemoehre]

Keep in mind, that making small codebases "more professional" by introducing more tools and rules (like you would do in an enterprise project) sometimes adds a lot of overhead to simple pragmatic things.

I will check it as soon as I find some time.