cli: add streams to rpc, generic 'spawn' command (#179732)

* cli: apply improvements from integrated wsl branch

* cli: add streams to rpc, generic 'spawn' command

For the "exec server" concept, fyi @aeschli.

* update clippy and apply fixes

* fix unused imports :(

cli/src/util/sync.rs

@@ -4,9 +4,11 @@
  *--------------------------------------------------------------------------------------------*/
 use async_trait::async_trait;
 use std::{marker::PhantomData, sync::Arc};
-use tokio::sync::{
-	broadcast, mpsc,
-	watch::{self, error::RecvError},
+use tokio::{
+	sync::{
+		broadcast, mpsc,
+		watch::{self, error::RecvError},
+	},
 };
 
 #[derive(Clone)]