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/peer_info.rs

@@ -16,6 +16,8 @@
 // You should have received a copy of the GNU General Public License
 // along with this program. If not, see <https://www.gnu.org/licenses/>.
 
+use crate::utils::interval;
+
 use fnv::FnvHashMap;
 use futures::prelude::*;
 use libp2p::{
@@ -36,8 +38,8 @@ use libp2p::{
 	Multiaddr,
 };
 use log::{debug, error, trace};
-use sc_network_common::utils::interval;
 use smallvec::SmallVec;
+
 use std::{
 	collections::hash_map::Entry,
 	pin::Pin,