Allow partial credit card payments on invoices

Adjust how credit card payments can be received and processed, both on the merchant side and on the customer's side, so a payment can be split into partial amounts instead of only the full invoice amount. Example: a customer with a transaction limit of $2,000 has an invoice for $3,000; the $3,000 charge keeps declining, and the customer wants to run $2,000 and then $1,000. On the merchant end it is only possible to charge the entire amount. The current workaround is creating entirely new jobs and new invoices to bring the amount under the threshold, which is described as a big pain in the butt.