Custom RPC request management for sync (#3029)

## Proposed Changes
Make `lighthouse_network` generic over request ids, now usable by sync

beacon_node/network/src/sync/range_sync/range.rs

@@ -45,8 +45,9 @@ use super::chain_collection::ChainCollection;
 use super::sync_type::RangeSyncType;
 use crate::beacon_processor::WorkEvent as BeaconWorkEvent;
 use crate::status::ToStatusMessage;
+use crate::sync::manager::Id;
 use crate::sync::network_context::SyncNetworkContext;
-use crate::sync::{BatchProcessResult, RequestId};
+use crate::sync::BatchProcessResult;
 use beacon_chain::{BeaconChain, BeaconChainTypes};
 use lighthouse_network::PeerId;
 use lighthouse_network::SyncInfo;
@@ -201,7 +202,7 @@ where
         peer_id: PeerId,
         chain_id: ChainId,
         batch_id: BatchId,
-        request_id: RequestId,
+        request_id: Id,
         beacon_block: Option<SignedBeaconBlock<T::EthSpec>>,
     ) {
         // check if this chunk removes the chain
@@ -300,7 +301,7 @@ where
         peer_id: PeerId,
         batch_id: BatchId,
         chain_id: ChainId,
-        request_id: RequestId,
+        request_id: Id,
     ) {
         // check that this request is pending
         match self.chains.call_by_id(chain_id, |chain| {
@@ -364,6 +365,7 @@ where
 
 #[cfg(test)]
 mod tests {
+    use crate::service::RequestId;
     use crate::NetworkMessage;
 
     use super::*;
@@ -494,10 +496,7 @@ mod tests {
         }
 
         /// Reads an BlocksByRange request to a given peer from the network receiver channel.
-        fn grab_request(
-            &mut self,
-            expected_peer: &PeerId,
-        ) -> (lighthouse_network::rpc::RequestId, BlocksByRangeRequest) {
+        fn grab_request(&mut self, expected_peer: &PeerId) -> (RequestId, BlocksByRangeRequest) {
             if let Some(NetworkMessage::SendRequest {
                 peer_id,
                 request: Request::BlocksByRange(request),