Move the handling of PROCESS_STATE_CHANGED to a single dedicated task.

[todo]

We currently handle PROCESS_STATE_CHANGED signaling in one task per launched process. This is a ridiculous amount of overhead.

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SunriseOS/loader/src/main.rs

Lines 235 to 245 in c2a92a4

	// TODO: Move the handling of PROCESS_STATE_CHANGED to a single dedicated task.
	// BODY: We currently handle PROCESS_STATE_CHANGED signaling in one
	// BODY: task per launched process. This is a ridiculous amount of
	// BODY: overhead.
	workqueue.clone().spawn(FutureObj::new(Box::new(async move {
	let mut current_state = ProcessState::Created;
	while current_state != ProcessState::Exited {
	if let Err(err) = process_static.wait_async(workqueue.clone()).await {
	error!("{:?}", err);
	return;
	}

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This issue was generated by todo based on a TODO comment in c2a92a4 when #542 was merged. cc @roblabla.