Credit card validation

[marcwrobel]

Add credit card validation support.

[marcwrobel]

See https://howtodoinjava.com/regex/java-regex-validate-credit-card-numbers/ for some details on how to validate credit cards.

[jycr]

It would be better to include this feature in another library.
In a pure SEPA processing platform, we does not need to deal with Credit Card number.

[marcwrobel]

@jycr, thank you for your feedback.

JBanking is meant to address general banking concerns, it is not only a library for SEPA. So I still think this feature can have its place in this library.

[jycr]

If you add an other functionnal domain (for example: "credit card"), have you planned to split this new domain into dedicated Maven module?
It would be great because we can import only needed modules in our application.

Indeed, we place great importance on minimizing the attack surface in our applications.

[marcwrobel]

@jycr, I do not plan to split jbanking in multiple modules for the time being because the library is still very small.

Fyi I planned to work mainly on #34 for the next few releases.