Grafana integration (#3913)

* Very WIP

* record_metrics macro works

* Integrate into service

* Licenses and documentation

* Remove unused Debugs, make respond function clearer

* Conform to line widths, fix service test

* Switch to storing the timestamps as millis instead

* Update core/grafana-data-source/src/lib.rs

Co-Authored-By: Kian Paimani <5588131+kianenigma@users.noreply.github.com>

* Transform timestamps to i64 in serialization

* Fix license date

* Binary sort to find selection range for metrics

* Obey maxDataPoints

* Run a cleaning future

* Newlines at EOF

* Update core/service/Cargo.toml

Co-Authored-By: Pierre Krieger <pierre.krieger1708@gmail.com>

* Update core/grafana-data-source/src/lib.rs

Co-Authored-By: Pierre Krieger <pierre.krieger1708@gmail.com>

* Fix indentation

* Improve select_points

* Made test more accurate

* Inprogress

* Use the same futures version as hyper for now

* Error handling

* Remove dependence on hyper's tokio feature

* Added target_os flag

* Update Cargo.toml

Co-Authored-By: Pierre Krieger <pierre.krieger1708@gmail.com>

* Simplify example

* Remove compat wildcard

* Updated lock file

* Fix indentation 😉

substrate/client/service/src/config.rs

@@ -73,6 +73,8 @@ pub struct Configuration<C, G, E = NoExtension> {
 	pub rpc_ws_max_connections: Option<usize>,
 	/// CORS settings for HTTP & WS servers. `None` if all origins are allowed.
 	pub rpc_cors: Option<Vec<String>>,
+	/// Grafana data source http port. `None` if disabled.
+	pub grafana_port: Option<SocketAddr>,
 	/// Telemetry service URL. `None` if disabled.
 	pub telemetry_endpoints: Option<TelemetryEndpoints>,
 	/// External WASM transport for the telemetry. If `Some`, when connection to a telemetry
@@ -151,6 +153,7 @@ impl<C, G, E> Configuration<C, G, E> where
 			rpc_ws: None,
 			rpc_ws_max_connections: None,
 			rpc_cors: Some(vec![]),
+			grafana_port: None,
 			telemetry_endpoints: None,
 			telemetry_external_transport: None,
 			default_heap_pages: None,