Some relayer improvments (#2902)

* added CLI arguments: full WS URI + separate for WS path URI component + additional log

* URI -> URL?

* added TODO

* fmt

bridges/relays/client-substrate/src/lib.rs

@@ -57,10 +57,15 @@ pub use bp_runtime::{
 /// Substrate-over-websocket connection params.
 #[derive(Debug, Clone)]
 pub struct ConnectionParams {
+	/// Websocket endpoint URL. Overrides all other URL components (`host`, `port`, `path` and
+	/// `secure`).
+	pub uri: Option<String>,
 	/// Websocket server host name.
 	pub host: String,
 	/// Websocket server TCP port.
 	pub port: u16,
+	/// Websocket endpoint path at server.
+	pub path: Option<String>,
 	/// Use secure websocket connection.
 	pub secure: bool,
 	/// Defined chain runtime version
@@ -70,8 +75,10 @@ pub struct ConnectionParams {
 impl Default for ConnectionParams {
 	fn default() -> Self {
 		ConnectionParams {
+			uri: None,
 			host: "localhost".into(),
 			port: 9944,
+			path: None,
 			secure: false,
 			chain_runtime_version: ChainRuntimeVersion::Auto,
 		}