This commit includes changes made to both the Article.php and ArticleList.php classes in the
QUI\ERP\Accounting directory. The setUser methods now accept a null type for the 'User' parameter,
giving more flexibility when calculating user details.

Type hinting was also improved in the ArticleList class. The variable type indicators were changed
from 'int|float' to 'int | float', and from 'Factor|QUI\\ERP\\Products\\Utils\\PriceFactor' to
'Factor | QUI\\ERP\\Products\\Utils\\PriceFactor', improving readability and clarity of code.

Lastly, the 'template' and 'articleTemplate' parameters in the 'toHTMLWithCSS' method now support
both 'bool' and 'string' types, adding flexibility to template usage.