Direct transfer transactions (PBL) improvements

[jakubtobiasz]

After delivering Pay by Link functionality, where we can choose a bank we want to be redirected directly, we have some improvements to be done.

Small wins 🏆

• Caching is done via a decoration, not directly in the service [ref]
• Creating a PBL transaction is unified and uses the same mechanisms as other types [ref]
• New payment details data is added to our PaymentDetails model [ref]
• PBL payment can be done via API [ref]

[arti0090]

@jakubtobiasz the caching I have done in last commit of "parent PR" - here it is 18aaa5b

I think it should solve the first checkbox but better if you would confirm it :)

[jakubtobiasz]

Ah, right. Missed that.