Django command to recover failed callbacks from Paygate

[igobranco]

We need to implement a Django command that recovers the failed success callbacks that the Paygate should have sent, but for one or another reason could deliver.

We already has an empty command:
https://github.com/fccn/ecommerce-plugin-paygate/blob/main/paygate/management/commands/failed_server_callbacks.py

This script then need to be executed at least daily by a cron based software.