babe: pass epoch data via intermediates (#4807)

* babe: pass epoch data via intermediates

* Switch to use Box<dyn Any> for intermediates

* Set intermediate.epoch to be Option

* Fix proposer should put out an empty intermediate

* Remove unnecessary encode/decode

* Add EpochData to block_import_params in slot worker

* Fix aura compile

* Fix integration test

substrate/client/consensus/slots/src/lib.rs

@@ -81,7 +81,7 @@ pub trait SimpleSlotWorker<B: BlockT> {
 	type Claim: Send + 'static;
 
 	/// Epoch data necessary for authoring.
-	type EpochData;
+	type EpochData: Send + 'static;
 
 	/// The logging target to use when logging messages.
 	fn logging_target(&self) -> &'static str;
@@ -119,6 +119,7 @@ pub trait SimpleSlotWorker<B: BlockT> {
 			Vec<B::Extrinsic>,
 			StorageChanges<<Self::BlockImport as BlockImport<B>>::Transaction, B>,
 			Self::Claim,
+			Self::EpochData,
 		) -> sp_consensus::BlockImportParams<
 			B,
 			<Self::BlockImport as BlockImport<B>>::Transaction
@@ -280,6 +281,7 @@ pub trait SimpleSlotWorker<B: BlockT> {
 				body,
 				proposal.storage_changes,
 				claim,
+				epoch_data,
 			);
 
 			info!(