event bus should be bound to scopes

[dustmop]

TODO from dispatch PR: https://github.com/qri-io/qri/pull/1653/files
// TODO(dustmop): Filter only events for this scope.

Let's say two methods are running at once, one is pulling a dataset and the other is getting status from an FSI directory. The first gets events from the bus about pull progress. The second should not be able to get any of these events, no matter how it tries to subscribe to them. This requires changing the bus such that events are bound to the current scope.

Certain subsystems, such as the filesystem watcher, or websockets, should still be able to see events globally.

[Arqu]

If I remember correctly, the idea was to use run-ids to separate the "subscribe" interfaces.
In that sense some auth mechanic should be present on the dispatch level and bellow that things should be trusted.
However, I think this should be configurable as external implementations using lib might not want that type of isolation for message passing.

[ramfox]

has this been closed by: #1870 ?

The PR adds profileid := profile.IDFromCtx(ctx) and passes that profile id to the event in bus.publish:

qri/event/event.go

Lines 153 to 170 in d451f6f

	func (b *bus) publish(ctx context.Context, typ Type, sessionID string, payload interface{}) error {
	b.lk.RLock()
	defer b.lk.RUnlock()
	log.Debugw("publish", "type", typ, "payload", payload)
	if b.closed {
	return ErrBusClosed
	}
	profileid := profile.IDFromCtx(ctx)
	e := Event{
	Type: typ,
	Timestamp: NowFunc().UnixNano(),
	SessionID: sessionID,
	ProfileID: profileid,
	Payload: payload,
	}