Final solution for taxClassId configuration

[rintisch]

Feature Request

Is your feature request related to a problem? Please describe.
According to the changelog documentation https://docs.typo3.org/p/extcode/cart/main/en-us/Changelog/7.3/Feature-339-TaxationOfServiceCostAsAnAncillaryService.html (or if the link some when might be outdated see 123b441#diff-6824b8d62c7724590e03ddb85fb20aee3537ad5eb787b15572798a7ca0250c83) the taxClassId configuration with negative values was only planned as temporary solution.

Describe the solution you'd like
A final solution for the problem. This might also solve #425