Sync Westend to Millau (#824)

* make finality verifier pallet instantiable

* add second instance of finality verifier pallet to the Millau runtime

* add Westend -> Millau headers relay

* use wss to connect to public westend nodes

* initialize with best_finalized_block

* typo

* Revert "initialize with best_finalized_block"

This reverts commit 954ed2832372d67618abc1a06d47e66faa93f674.

* pass VoterSet by ref

* new bridge initialization code

* loop upper bound

* Polkadot -> Westend

* fixed tests compilation

* default-features

* assert

bridges/relays/clients/substrate/src/client.rs

@@ -95,7 +95,12 @@ impl<C: Chain> Client<C> {
 
 	/// Build client to use in connection.
 	async fn build_client(params: ConnectionParams) -> Result<RpcClient> {
-		let uri = format!("ws://{}:{}", params.host, params.port);
+		let uri = format!(
+			"{}://{}:{}",
+			if params.secure { "wss" } else { "ws" },
+			params.host,
+			params.port,
+		);
 		let mut config = RpcConfig::with_url(&uri);
 		config.max_subscription_capacity = MAX_SUBSCRIPTION_CAPACITY;
 		let client = RpcClient::new(config).await?;

bridges/relays/clients/substrate/src/lib.rs

@@ -44,6 +44,8 @@ pub struct ConnectionParams {
 	pub host: String,
 	/// Websocket server TCP port.
 	pub port: u16,
+	/// Use secure websocket connection.
+	pub secure: bool,
 }
 
 impl Default for ConnectionParams {
@@ -51,6 +53,7 @@ impl Default for ConnectionParams {
 		ConnectionParams {
 			host: "localhost".into(),
 			port: 9944,
+			secure: false,
 		}
 	}
 }