Add log to Sales Order and Invoice for Payment terms been changed

Payment terms message is added to Logs SO/Invoice.

To check this, the user needs to do the next steps:

• Create new SO -> Add item and Customer -> Process;
• Reopen SO -> Add Payment terms -> Save;
• Reopen SO again -> Observe Logs;
• Shipped Ship Order -> Create Invoice;
• Add Payment terms -> Observe Logs -> Save;
• Reopen Invoice -> Observe Logs.