Implement COM Fremdkostenposition

[hf-kklein]

https://www.bo4e.de/dokumentation/komponenten/com-fremdkostenposition
requires

• Implement COM Preis #145
• Implement COM Betrag #144
• The validation will have short comings due to Remove Waehrungscode or merge Waehrungscode and Waehrungseinheit #126 (how to compare Betrag and Preis if one of them uses Waehrungscode and the other uses Waehrungseinheit)
• von and bis should be inclusive / exklusive
• for EIC see Implement EIC Code Validation #147