[FEATURE] Making item-table more flexible

__Tasks:__
- [x] done
- [x] got feedback

__Informations:__

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| Tests pass?   | none
| Fixed tickets | none
| BC Breaks | yes. changes must be performed in sales-order-bundle
| Doc           | none