PostFinance camt.053 xml support

[kosli]

As I saw that you have an importer for MT940 files from PostFinance and I am looking for an importer for the camt.053 xml files from PostFinance, I thought asking if you have the need for importing camt.053 files too?

[tarioch]

Actually this was contributed by @przemator I just had a generic MT940 importer and the ZKB one. Maybe he can help.