Internal `CreateProcessFactory` should be refactored to a non-static and DI'ble approach

[Stefan Bürk]

Basically, there are different ways to implement class
factories. Using a final class with a static method
without a interface on the factory class or the class
to be created by the factory is considerable bad and
prevents proper exchanging things.

A industry wide approach for providing good and exchangable
factories is following way:

• Build upon a factory class interface, ex. MyFactoryInterface
• Providing a abstract factory class implementing the interface
  and the default behaviour, ex. AbstractFactory
• Provide a slim class implementation based on the AbstractFactory,
  MyFactory extends AbstractFactory
• Add a DI configuration to retrieve the MyFactory based on the
  MyFactoryInterface.
• Use DI in code places to retrieve the factory based on the interface
  and operate with this.

Therefore, the implementation should change - even staying internal.
That helps more experienced developers but not making it a API for now.