feat: quiqqer/invoice#104

ajax/calcBruttoPrice.php

ajax/products/calc.php

bin/backend/controls/articles/Article.css

bin/backend/controls/articles/Article.js

bin/backend/controls/articles/ArticleList.js

locale.xml

src/QUI/ERP/Accounting/ArticleDiscount.php

src/QUI/ERP/Accounting/ArticleList.php

src/QUI/ERP/Accounting/ArticleListUnique.php

src/QUI/ERP/Accounting/Calc.php

src/QUI/ERP/Utils/User.php