Integrate SEPA Credit Transfer QR-Code

[dragotin]

It would be awesome to integrate the SEPA Credit Transfer QR-Code to the Kraft output documents (invoices). With that, customers can easily transfer the money using mobile apps. https://en.wikipedia.org/wiki/EPC_QR_code

https://epc-qr.eu/ provides a free API to generate the QR-Code, which for example German Sparkasse tries to charge for API- or library usage.

The integration should be optional.