Parachains pallet benchmarks (#1436)

* added parachains pallet benchmarks

* deduplicate insertion of bridged header

* pruning weight

* fixes

* fix compilation

bridges/relays/bin-substrate/src/chains/rialto_parachains_to_millau.rs

@@ -49,5 +49,5 @@ pub type RialtoParachainsToMillauSubmitParachainHeadsCallBuilder =
 	DirectSubmitParachainHeadsCallBuilder<
 		RialtoParachainsToMillau,
 		millau_runtime::Runtime,
-		millau_runtime::WitRialtoParachainsInstance,
+		millau_runtime::WithRialtoParachainsInstance,
 	>;

bridges/relays/lib-substrate-relay/src/parachains/source.rs

@@ -161,6 +161,6 @@ where
 			.iter_nodes()
 			.collect();
 
-		Ok(parachain_heads_proof)
+		Ok(ParaHeadsProof(parachain_heads_proof))
 	}
 }

bridges/relays/parachains/src/parachains_loop.rs

@@ -664,7 +664,7 @@ mod tests {
 						.ok_or(TestError::MissingParachainHeadProof)?,
 				);
 			}
-			Ok(proofs)
+			Ok(ParaHeadsProof(proofs))
 		}
 	}