Support for Verification of Payee

[ampaze]

I hope this PR can spark a discussion on how to implement VoP.

For now this

• checks if VoP is needed for the SEPA transfer, which it will be starting in October 2025.
• sends a VoP request along with the SEPA transfer request
• looks at the response of the bank

PS: Gerne auch auf Deutsch.

refs #477

[Philipp91]

Nice!

It seems like the HIVPP and HKVPA part is still missing. Is that because you simply made some progress so far and wanted to put it out there, or because the pieces that are in this PR so far already work end-to-end (i.e. we wouldn't need these other two segments to make banks accept transfers at least)?

[Philipp91]

What does it mean if we pretend that we support all formats? Does the bank somehow get to choose one of them and then we have to be able to do something with it? Or is it not the library but instead the application (caller of phpFinTS) that would need to understand this?

[ampaze]

I haven't gotten that far, as I have no way to test this. My guess is that the bank will chose one format from that list.

[ampaze]

Our banks don't have any support for VoP yet, so i started implementing this without being able to test it. Maybe someone with a VoP ready bank can use it to help development. Also I wanted to get feedback early on, as I am still in the process of understanding VoP and how phpFinTS should implement it.