[Feature request] Fullcone NAT for nftables

Created by: huyz-git

xanmod kernel had already added fullcone nat support for legacy xtables https://github.com/xanmod/linux/commit/58db8824f8d7b598961275348e544bffbcc5a16d It will be great if it could also add fullcone nat support for nftables: https://github.com/fullcone-nat-nftables/nft-fullcone