Add transaction partner code on the invoice template

[vohmar]

Starting from 2024 EIS is mandated to file monthly reporting for balance and payment data. Together with this we need to add transaction partner code to our invoice templates together with registry and VAT numbers

Transaction partner code / tehingupartneri kood: TP 012311

In reality this number is important only to other Estonian orgs that also have transaction partner code. So we have to options here

1. add this nr to invoice template by default and thus display this on every created invoice
2. add this nr only to invoices for orgs that also have such a number ie public sector organizations and private sector organizations established by Estonian Gov. For this we could add a special parameter to the customer/partner profile. So if auction customer fills this field with their own transaction partner code we will also include our code in the invoices issued to those clients.

Suggest to go with the second option. We have had few instances of local municipalities participating in auctions