Port SEPA modules to new API

Fix an important regression in account_banking_sepa_direct_debit: "Date of Last Debit" was not set any more
Proper write of date_done with account_banking_payment_export is installed without account_banking_payment_transfer
Add post-install script for date_sent on payment.order

account_banking_payment_transfer/__init__.py

@@ -1 +1,2 @@
 from . import model
+from .post_install import set_date_sent