Donations (Payment independent of Orders)

There should be a way for clients or customers to be able to make arbitrary payments to the cart/store. This can be used in multiple ways. One as a donation or by me a beer setup. And the other for special use cases when the store needs to be able to accept money and other payments that are not attached to an order or product. This would be then listed an a payment or donation (defined by store admin) on the users page or order list. This way the payments can be filtered or separated from standard orders.