Move bitswap to its own crate (#12242)

* Introduce `sc-network-bitswap`

Move the bitswap protocol out of `sc-network` to its own crate.

* Improve test coverage

* Remove mention of bitswap from `sc-network`

* Fix documentation

* Fix clippy and remove the void dependency

* Remove unneeded trait bound and bump prost to 0.11

substrate/client/network/src/behaviour.rs

@@ -17,7 +17,6 @@
 // along with this program. If not, see <https://www.gnu.org/licenses/>.
 
 use crate::{
-	bitswap::Bitswap,
 	discovery::{DiscoveryBehaviour, DiscoveryConfig, DiscoveryOut},
 	peer_info,
 	protocol::{message::Roles, CustomMessageOutcome, NotificationsSink, Protocol},
@@ -32,8 +31,7 @@ use libp2p::{
 	identify::IdentifyInfo,
 	kad::record,
 	swarm::{
-		behaviour::toggle::Toggle, NetworkBehaviour, NetworkBehaviourAction,
-		NetworkBehaviourEventProcess, PollParameters,
+		NetworkBehaviour, NetworkBehaviourAction, NetworkBehaviourEventProcess, PollParameters,
 	},
 	NetworkBehaviour,
 };
@@ -79,8 +77,6 @@ where
 	peer_info: peer_info::PeerInfoBehaviour,
 	/// Discovers nodes of the network.
 	discovery: DiscoveryBehaviour,
-	/// Bitswap server for blockchain data.
-	bitswap: Toggle<Bitswap<B>>,
 	/// Generic request-response protocols.
 	request_responses: request_responses::RequestResponsesBehaviour,
 
@@ -214,7 +210,6 @@ where
 		block_request_protocol_config: ProtocolConfig,
 		state_request_protocol_config: ProtocolConfig,
 		warp_sync_protocol_config: Option<ProtocolConfig>,
-		bitswap: Option<Bitswap<B>>,
 		light_client_request_protocol_config: ProtocolConfig,
 		// All remaining request protocol configs.
 		mut request_response_protocols: Vec<ProtocolConfig>,
@@ -239,7 +234,6 @@ where
 			substrate,
 			peer_info: peer_info::PeerInfoBehaviour::new(user_agent, local_public_key),
 			discovery: disco_config.finish(),
-			bitswap: bitswap.into(),
 			request_responses: request_responses::RequestResponsesBehaviour::new(
 				request_response_protocols.into_iter(),
 				peerset,
@@ -338,16 +332,6 @@ fn reported_roles_to_observed_role(roles: Roles) -> ObservedRole {
 	}
 }
 
-impl<B, Client> NetworkBehaviourEventProcess<void::Void> for Behaviour<B, Client>
-where
-	B: BlockT,
-	Client: HeaderBackend<B> + 'static,
-{
-	fn inject_event(&mut self, event: void::Void) {
-		void::unreachable(event)
-	}
-}
-
 impl<B, Client> NetworkBehaviourEventProcess<CustomMessageOutcome<B>> for Behaviour<B, Client>
 where
 	B: BlockT,