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.

This commit addresses the issue of PHPStan not recognizing certain classes for type validation
within our PHP codebase. This is done by adding these classes to the PHPStan configuration as
ignored errors. This ensures accuracy in our static analysis for errors and warnings. Key classes
such as QUI\\ERP\\Process, QUI\\ERP\\Accounting\\Calc and QUI\\ERP\\Accounting\\ArticleList have
been catered to.

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.

Changed the variable name `$OutputProvider` to `$outputProvider` to adhere to camelCase naming
standards. Also moved the instantiation of `$outputProvider` inside an if block to prevent
unnecessary instantiation when `$outputProvider` is empty.

Related: pcsg/kunden/libellio/b2c/core#196

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

Related: #105

Related: #105

Related: #105

Related: #104

fix: correctly check if translation of unit exists

See merge request !151

(cherry picked from commit 21a31f8f)

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

Related: pcsg/buero#476

Related: pcsg/buero#425

Related: pcsg/buero#456

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