Resolved an issue in src/QUI/ERP/Money/Price.php file where there was a merge conflict happening
between different versions. Now, the file is ready for further contributions.

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.

Removed some superfluous comments and exception declaration in the `convertUserToErpUser` function
within the `User.php` class. These comments were not adding any useful information, and the
exception mentioned was not being thrown, hence their removal.

Updated calcArticleList method in Calc.php to ignore PHPStan warnings using the
`@phpstan-ignore-line` and `@phpstan-ignore-next-line` directives. Also, added a TODO comment
regarding net calculations.

In this commit, several changes have been made to streamline the Manufacturer and Process classes
within the ERP module:

- Replaced the non-empty check for 'firstname' and 'lastname' attributes in the User class with an
`empty()` function, resulting in cleaner code without changing the functionality.
- Replaced the argument in `User->activate()` from `false` to `''` for consistency.
- Removed unnecessary annotations and some unused `protected` properties from the Process class.
- Altered the procedure to retrieve `salesOrder` from the Entity in the Process class. Now, the
method first tries to retrieve it via `getPaymentDataEntry()`, and if unavailable, it attempts to
fetch it using `getCustomDataEntry()`. This ensures a more robust and reliable retrieval of the
'salesOrder' property.
- Added `@phpstan-ignore-next-line` in the Processes class to prevent phpstan from throwing
unwarranted warnings regarding the following code line in specific scenarios.

Related: #103

In this commit, several enhancements are made in the ajax price calculation PHP files including
more verbose error logging and minor refactoring of the calculation itself. Instead of adding an
error message in QUI, we now add detailed error handling using QUI\System\Log.

Additionally, we have improved file handling in `ajax/output/sendMail.php` by ensuring the file is
an instance of `QUI\Projects\Media\File` or `QUI\Projects\Media\Image` before attaching it.

Lastly, we added an option for parsing in method getCustomerFiles of the ErpEntityInterface. This
commit will make the scripts more efficient and robust against errors.

Related: #103

Changed the constants 'TYPE_INVOICE_REVERSAL' and 'TYPE_INVOICE_CANCEL' to 'PAYMENT_STATUS_ERROR'
and 'PAYMENT_STATUS_CANCELED' respectively. This will ensure that the payment status are correctly
identified and processed.

In OutputTemplate.php, a check has been added to ensure the existence of the
'QUI\\HtmlToPdf\\Document' class before using it. If the class does not exist, an error message is
logged, and an exception is thrown indicating that the html2pdf module is missing. This fix is
aimed at avoiding potential errors that may occur due to the absence of the required module.

Related: pcsg/buero#491

fix: declaration of ArticleList::toHTMLWithCSS must be compatible with ArticleListUnique::toHTMLWithCSS

feat(ArticleListUnique): toHTML() can be passed to template engine and thus settings / variables can be passed on

Related: order-simple-checkout#12

(cherry picked from commit 21a31f8f)

Co-authored-by: Patrick Müller <p.mueller@pcsg.de>

Related: pcsg/buero#425

Related: pcsg/buero#344
Related: pcsg/buero#436

Related: pcsg/buero#344
Related: pcsg/buero#436

Customer id was not passed on correctly.
So it happened that the customer id did NOT get into the erp entities.

Related: pcsg/buero#453