Generalize the Consensus Infrastructure (#883)

* Split out Consensus
* Supply ImportQueue through network-service
  - simplify ImportQueue.import_blocks
  - remove Deadlock on import_block
  - Adding Verifier-Trait
  - Implement import_queue provisioning in service; allow cli to import
* Allow to actually customize import queue
* Consensus Gossip: Cache Message hash per Topic

substrate/core/sr-primitives/src/lib.rs

@@ -59,9 +59,10 @@ pub mod testing;
 
 pub mod traits;
 pub mod generic;
-pub mod bft;
 pub mod transaction_validity;
 
+pub type Justification = Vec<u8>;
+
 use traits::{Verify, Lazy};
 
 #[cfg(feature = "std")]