message: network-core: Remove gossip::NodeIdError
  It follows NodeId into oblivion.
diff: use chain_core::property::{Deserialize, Serialize};
  -use std::{error, fmt, net::SocketAddr};
  -
  -#[derive(Clone, Debug)]
  -pub enum NodeIdError {
  - InvalidSize(usize),
  -}
  -
  -impl error::Error for NodeIdError {
  - fn source(&self) -> Option<&(dyn error::Error + 'static)> {
  - None
  - }
  -}
  -
  -impl fmt::Display for NodeIdError {
  - fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
  - match self {
  - NodeIdError::InvalidSize(size) => write!(f, "invalid node id size: {}", size),
  - }
  - }
  -}
  +use std::net::SocketAddr;
  /// Abstract trait for data types representing gossip about network nodes.
  pub trait NodeGossip {
  