Move code from sc-network-common back to sc-network (#13592)

* Move service tests to `client/network/tests`

These tests depend on `sc-network` and `sc-network-sync` so they should
live outside the crate.

* Move some configs from `sc-network-common` to `sc-network`

* Move `NetworkService` traits to `sc-network`

* Move request-responses to `sc-network`

* Remove more stuff

* Remove rest of configs from `sc-network-common` to `sc-network`

* Remove more stuff

* Fix warnings

* Update client/network/src/request_responses.rs

Co-authored-by: Dmitry Markin <dmitry@markin.tech>

* Fix cargo doc

---------

Co-authored-by: Dmitry Markin <dmitry@markin.tech>

substrate/client/network/src/discovery.rs

@@ -46,6 +46,8 @@
 //! active mechanism that asks nodes for the addresses they are listening on. Whenever we learn
 //! of a node's address, you must call `add_self_reported_address`.
 
+use crate::{config::ProtocolId, utils::LruHashSet};
+
 use array_bytes::bytes2hex;
 use futures::prelude::*;
 use futures_timer::Delay;
@@ -73,7 +75,6 @@ use libp2p::{
 	},
 };
 use log::{debug, info, trace, warn};
-use sc_network_common::{config::ProtocolId, utils::LruHashSet};
 use sp_core::hexdisplay::HexDisplay;
 use std::{
 	cmp,
@@ -904,6 +905,7 @@ mod tests {
 	use super::{
 		kademlia_protocol_name, legacy_kademlia_protocol_name, DiscoveryConfig, DiscoveryOut,
 	};
+	use crate::config::ProtocolId;
 	use futures::prelude::*;
 	use libp2p::{
 		core::{
@@ -915,7 +917,6 @@ mod tests {
 		swarm::{Executor, Swarm, SwarmEvent},
 		yamux, Multiaddr,
 	};
-	use sc_network_common::config::ProtocolId;
 	use sp_core::hash::H256;
 	use std::{collections::HashSet, pin::Pin, task::Poll};