Initial user pages cleanup.

- Replace the add links per payment method with one link showing a list
  of add links per payment method, skipped if only one present (same as for
  product types).
- Remove the useless, disabled view page, default to edit.
- Hide the card number and card type fields on edit since they aren't editable.
- Hide the Default checkbox instead of disabling it.
- Delete the cards from the system instead of just marking them as inactive.