impl Debug for sc_service::Configuration (#6400)

* Initial commit

Forked at: 252416d385
No parent branch.

* Make sc_service::Configuration derive Debug

* Replace task_executor fn's input by proper TaskExecutor type (cleaner)

* impl From<Fn> for TaskExecutor

* Update client/cli/src/runner.rs

* Add some doc, examples and tests

* Replace Deref by fn spawn as suggested

Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>

substrate/utils/browser/src/lib.rs

@@ -17,7 +17,6 @@
 
 use futures01::sync::mpsc as mpsc01;
 use log::{debug, info};
-use std::sync::Arc;
 use sc_network::config::TransportConfig;
 use sc_service::{
 	AbstractService, RpcSession, Role, Configuration,
@@ -64,7 +63,7 @@ where
 		network,
 		telemetry_endpoints: chain_spec.telemetry_endpoints().clone(),
 		chain_spec: Box::new(chain_spec),
-		task_executor: Arc::new(move |fut, _| wasm_bindgen_futures::spawn_local(fut)),
+		task_executor: (|fut, _| wasm_bindgen_futures::spawn_local(fut)).into(),
 		telemetry_external_transport: Some(transport),
 		role: Role::Light,
 		database: {