refactor(iroh-net): remove iroh-net::config::Node since limited to its used fields it's redundant

[divagant-martian]

Description

the Node type contains:

iroh/iroh-net/src/config.rs

Lines 157 to 174 in f2f3ead

	pub struct Node {
	/// The public key or PeerID, the primary identifier of this node.
	pub key: PublicKey,
	/// DNS name of the peer.
	pub name: Option<String>,
	/// Direct IP addresses of this Node.
	///
	/// These are the IP addresses this node is listening on.
	pub addresses: Vec<IpAddr>,
	/// Endpoints on which we think the node is reachable.
	///
	/// These are populated from STUN results as well as local LAN addresses.
	pub endpoints: Vec<SocketAddr>,
	/// DERP-in-IP:port ("127.3.3.40:N") endpoint. Only stores the `N`.
	///
	/// If this nodes expected to be reachable via DERP relaying.
	pub derp: Option<u16>,
	}

from these fields:

• name is always None, so unused.
• addresses is always calculated from the the endpoints so it can be removed.
  After this, the only remaining fields are the key, endpoints and derp region. This is equivalent to the NodeAddr type, making Node redundant
  

  iroh/iroh-net/src/magic_endpoint.rs

  Lines 20 to 29 in f2f3ead

  	/// Adress information for a node.
  	#[derive(Debug)]
  	pub struct NodeAddr {
  	/// The node's public key.
  	pub node_id: PublicKey,
  	/// The node's home DERP region.
  	pub derp_region: Option<u16>,
  	/// Socket addresses where this node might be reached directly.
  	pub endpoints: Vec<SocketAddr>,
  	}

Notes & open questions

Change checklist

• Self-review.
• Documentation updates if relevant.
• Tests if relevant.

[Frando]

LGTM!