[FEATURE] Extended product manager

Extended ProductManager.

__Tasks:__

- [x] add new method to change the current product state
- [x] add new property to prevent an update of the changed date
- [x] gather feedback for my changes

__Informations:__

| Q             | A
| ------------- | ---
| Tests pass?   | yes
| Fixed tickets | none
| BC Breaks     | none
| Doc           | none