Update repo structure to https://github.com/AlexSkrypnyk/scaffold

[AlexSkrypnyk]

Download the latest code from Scaffold repo (actual code, not the release).

• Update composer.json with the structure from Scaffold. Preserve the values of the existing fields, but order the fields as per Scaffold's composer.json. Add missing fields.

• Add Renovate config from Scaffold

• Add/update all GitHub actions and configs to be per Scaffold. Note that the test GHA workflow should NOT be used as CircleCI is used for this repo and should be preserved.

• Update readme to use the structure from Scaffold, including the generated logo (circle). Transfer the usage examples into the readme structure from Scaffold

• Add PHPStan config and fix all newly found violations

• Do not create docs folder and CI action - this project is too small to have extensive docs.

Make sure that CI passes.

Similar task for reference: AlexSkrypnyk/shellvar#17

[AlexSkrypnyk]

closed in #44