server/state: add spawn_internal_task and use it for websockets

is a helper to spawn an internal tokio task without it showing up
in the task list

it is still tracked for reload and notifies the last_worker_listeners

this enables the console to survive a reload of proxmox-backup-proxy

Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>

src/api2/node.rs

@@ -267,7 +267,7 @@ fn upgrade_to_websocket(
 
         let (ws, response) = WebSocket::new(parts.headers)?;
 
-        tokio::spawn(async move {
+        crate::server::spawn_internal_task(async move {
             let conn: Upgraded = match req_body.on_upgrade().map_err(Error::from).await {
                 Ok(upgraded) => upgraded,
                 _ => bail!("error"),