Add support for NAT Traversal

[kishansagathiya]

Task summary

Few days ago me and @noot were discussing about whether p2p circuit relay should be enabled in gossamer and what are the benefits and possible risks of it. Creating this issue to get clarity on a

• At the moment, Peers that are behind NAT cannot connect to gossamer network.
• Is it important for us to take care of NAT traversal? Are most of our users (or users of polkadot) likely to be behind NAT?
• If you do some research on various NAT Traversal protocols offered by libp2p like AutoNAT, p2p circuit relay, STUN, UPnP, etc. See which of these would make sense for us to support.
• Check if substrate/polkadot is using any of these

Specification reference

Other information and links

[danforbes]

Related Substrate Issue https://github.com/paritytech/polkadot-sdk/issues/567

[timwu20]

Given that substrate doesn't support this I don't think we need to. Closing this.