nat: T4367: Move nat rules from /tmp to /run/nftables_nat.conf
nat: T4367: Move nat rules from /tmp to /run/nftables_nat.conf

Move nftables nat configuration from /tmp to /run
As we have for other services like firewall, conntrack
Don't remove the config file '/run/nftables_nat.conf' after commit

vyos/vyos-1x,vyos/vyos-1x,vyos/vyos-1x,vyos/vyos-1x