refactor(notification): use new queue package (#9360)

# Which Problems Are Solved

The recently introduced notification queue have potential race conditions.

# How the Problems Are Solved

Current code is refactored to use the queue package, which is safe in
regards of concurrency.

# Additional Changes

- the queue is included in startup
- improved code quality of queue

# Additional Context

- closes https://github.com/zitadel/zitadel/issues/9278

internal/eventstore/event_base.go

@@ -22,7 +22,7 @@ type BaseEvent struct {
 	ID        string
 	EventType EventType `json:"-"`
 
-	Agg *Aggregate
+	Agg *Aggregate `json:"-"`
 
 	Seq                           uint64
 	Pos                           float64