[Feature request] IP rules for nftables (OpenWrt 22.03)

[Marek Adamski]

OpenWrt 22.03 comes with nftables instead of iptables and /etc/firewall.user has been replaced with /etc/nftables.d/*.nft

All *.nft files in this directory are included by the firewall4 ruleset
within the inet/fw4 table context which allows referencing named sets
declared and populated by the firewall configuration.