Add SCL-directory information for BICs

[lukaszett]

The SCL-directory contains a list of all valid BICs alongside information on the banks' participation in the different available payment schemes (credit transfer, direct debit, B2B direct debit, card clearing).

We could use this directory two fold:

• To automatically check which BIC are not yet present in the registry.
• To enrich the BIC-class with attributes on whether or not this banks supports a given service.

The German federal bank offers a continuously updated CSV at the following link: https://bundesbank.de/scl-directory

Here is more information on the directory. (sadly only in German)