Create Audit Log / Posting Tables

[jedateach]

Important for money-based systems is keeping a record of everything that happens and changes. This means creating some kind of audit trail, known in the accounting world as a posting table. Every time a product or order is updated, a record is made of this change. This data isn't used often, but will be very useful if ever needed, as it provides accountability.

There are some OrderStatusLog classes and functions which are not actually used currently.

[jedateach]

This somewhat relates to the way PaymentMessage works in the omnipay wrapper module.