Action and script to backup config.xml over scp with a cron job in GUI.
Must be placed in /usr/local/opnsense/service/conf/actions.d/
Replace {USER} with an user that has the appropriate ssh key to access the backup host.
Execute $ service configd restart afterwards.
Must be placed in /usr/home/scp-backup.sh (or change the path in actions_scp-backup.conf).
Replace {USERID} with the ID of the user {USER} for accessing the backup host {HOST}.