Filter gossipsub message duplication (#736)

* Add duplication prevention to gossipsub

* Clean up topic logs

* Add content addressed messages for gossip

beacon_node/network/src/sync/manager.rs

@@ -58,9 +58,9 @@
 //! if an attestation references an unknown block) this manager can search for the block and
 //! subsequently search for parents if needed.
 
-use super::message_processor::PeerSyncInfo;
 use super::network_context::SyncNetworkContext;
 use super::range_sync::RangeSync;
+use crate::message_processor::PeerSyncInfo;
 use crate::service::NetworkMessage;
 use beacon_chain::{BeaconChain, BeaconChainTypes, BlockProcessingOutcome};
 use eth2_libp2p::rpc::methods::*;