rpc server: add rate limiting middleware (#3301)

Add RPC server rate limiting which can be utilized by the CLI
`--rpc-rate-limit <calls/per minute>`

Resolves first part of
https://github.com/paritytech/polkadot-sdk/issues/3028

//cc @PierreBesson @kogeler  you might be interested in this one

---------

Co-authored-by: James Wilson <james@jsdw.me>
Co-authored-by: Xiliang Chen <xlchen1291@gmail.com>

substrate/client/service/src/config.rs

@@ -39,6 +39,7 @@ use sp_core::crypto::SecretString;
 use std::{
 	io, iter,
 	net::SocketAddr,
+	num::NonZeroU32,
 	path::{Path, PathBuf},
 };
 use tempfile::TempDir;
@@ -102,6 +103,8 @@ pub struct Configuration {
 	pub rpc_port: u16,
 	/// The number of messages the JSON-RPC server is allowed to keep in memory.
 	pub rpc_message_buffer_capacity: u32,
+	/// RPC rate limit per minute.
+	pub rpc_rate_limit: Option<NonZeroU32>,
 	/// Prometheus endpoint configuration. `None` if disabled.
 	pub prometheus_config: Option<PrometheusConfig>,
 	/// Telemetry service URL. `None` if disabled.

substrate/client/service/src/lib.rs

@@ -403,6 +403,7 @@ where
 		id_provider: rpc_id_provider,
 		cors: config.rpc_cors.as_ref(),
 		tokio_handle: config.tokio_handle.clone(),
+		rate_limit: config.rpc_rate_limit,
 	};
 
 	// TODO: https://github.com/paritytech/substrate/issues/13773