Clean-up Gin PHP

Problem/Motivation

• Turn every procedural code into OO code
• This will remove all the include files, maybe more
• Optimize for low hanging fruit

Further improvements are planned for after the Drupal core 11.3 release. Here we mainly address the legacy stuff that shouldn't land in core in the first place.

See also related issues, and get started with this one, when those have been finalized.