Add support for TCP in TPROXY

[gaby]

@nadoo I notice the implementation is based on another repo. That repo has both UDP and TCP implementations, but the TCP implementation was never added to this repo.

https://github.com/KatelynHaworth/go-tproxy/blob/master/tproxy_tcp.go

Iptables docs mention TPROXY supports both udp and tcp: https://manpages.debian.org/bookworm/iptables/iptables-extensions.8.en.html#TPROXY