Generic keystore (#3008)

* Add KeyTypeId.

* Implement clone for sr25519::Pair.

* Extend Pair with to_raw_vec.

* Implement TypedKey for Signature and Pair.

* Add trait Public.

* Make keystore generic.

* Fixup clone.

* Fix tests.

* Update service.

* Fix imports.

* Fix build.

* Fix babe build.

* Fix subkey build.

* Make authority setup generic.

* Update node-template.

* Fix build.

* Remove unsafe code.

* Fix tests.

substrate/node-template/src/service.rs

@@ -65,8 +65,8 @@ construct_service_factory! {
 				FullComponents::<Factory>::new(config)
 			},
 		AuthoritySetup = {
-			|service: Self::FullService, key: Option<Arc<Pair>>| {
-				if let Some(key) = key {
+			|service: Self::FullService| {
+				if let Some(key) = service.authority_key::<Pair>() {
 					info!("Using authority key {}", key.public());
 					let proposer = Arc::new(ProposerFactory {
 						client: service.client(),
@@ -77,7 +77,7 @@ construct_service_factory! {
 						.ok_or_else(|| ServiceError::SelectChainRequired)?;
 					let aura = start_aura(
 						SlotDuration::get_or_compute(&*client)?,
-						key.clone(),
+						Arc::new(key),
 						client.clone(),
 						select_chain,
 						client,