fwknopd not working with nftables

[geo99918]

fwknopd is not working with newer kernels that use nftables.

see: https://forum.openwrt.org/t/fwknop-on-x86-64-22-03-2/143855

[Andrey Butirsky]

This probably is a duplicate of #107

[David Andreoletti]

@mrash This is definitely a duplicate of #107. Would you mind closing #352 ?

[Michael Rash]

Yes, agreed, closing this one as a dupe of #107.