Deposit and credit invoice generation option

[vohmar]

We have a request from auction participant to have invoice for their deposit payment and if they do not win then credit invoice for returning the paid deposit.

This is not needed for most participants so let's add this as optional feature - where user has to "press the button" to generate and download the deposit and if returned then also the credit invoice

I suggest butting the invoice and if applicable the credit invoice generation option to the /offers/ view in the "Deposit Payments" table as the button(s) to the end of the authenticated users record. The result should be downloaded pdf - no need to store the invoice in auction portal or send it anywhere.