Base class details to a Salesforce Payments payment. See Salesforce Payments documentation for how to gain access and
configure it for use on your sites.
Some payment types like SalesforcePaymentMethod.TYPE_CARD contain additional details like the card brand, or
the last 4 digits of the card number. Details to those payments will be of a specific subclass of this class like
SalesforceCardPaymentDetails. Other payment types have no additional information so their details are
represented by an object of this base type.