Add support for re-using tokenization authorization

[pierre]

Adyen doesn't have a standalone tokenization API: tokens (i.e. recurringDetailReference) can only be created when triggering a real payment.

The standard flow is to tokenize by triggering a $0 auth (voided right away), before triggering a real payment (auth+capture or auto-capture). This has potentially two drawbacks:

• Cost: Adyen charges per API call
• Auth rate: it has been seen in the field that the subsequent auth has a higher rate of refusal

In the case where tokenization is performed outside of Kill Bill (e.g. PCI vault), we would like the Adyen plugin to re-use that auth when triggering the first payment. The new flow would be:

• External system tokenizes by triggering an auth for $N (full payment amount)
• External system creates a payment method in Kill Bill, specifying the following plugin properties:
  • token: value of recurringDetailReference
  • authPspReference: value of the pspReference returned by Adyen for the auth
• When Kill Bill invokes purchasePayment (either through direct payment APIs or via invoice payment APIs), if this authPspReference property is found in the payment method, it should:
  • Call executeInitialTransaction (TransactionType.AUTHORIZE, skipGw=true) to sync the authorization record. The shouldSkipAdyen code branch will need to be updated to make sure the pspReference is correctly stored.
  • Call capturePayment (normal capture call for $N)
  • Upon success, update the payment method to remove the authPspReference property (so that it is not re-used)

Notes:

• one side effect would be that PaymentPluginStatus now returns PENDING instead of PROCESSED (effectively making the purchasePayment call asynchronous). Kill Bill should still be able to handle it though.
• it is assumed that the original auth amount would match the purchase amount. If not, the payment may be under- or over- captured.