Use netlink interface directly instead of iptables user space

[aojea]

As done for kubernetes-sigs/kube-network-policies#136 , it will allow us to use distroless images and reduce dependencies

References:

• https://github.com/aojea/kindnet/blob/main/docs/nftables-netlink.md
• [WIP] nf2go: convert nftables rules to golang code google/nftables#298
• Use nftables netlink api directly aojea/kindnet#139