Replace old iptables-legacy with -nft

Alma guide:

dnf remove iptables-legacy iptables-services
dnf install iptables-nft iptables-nft-services
mv /etc/sysconfig/iptables.rpmsave /etc/sysconfig/iptables
systemctl enable iptables
mv /etc/sysconfig/ip6tables.rpmsave /etc/sysconfig/ip6tables
systemctl enable ip6tables