fix(event handling): use internal pubsub for view update (#1118)

* start sub

* start implement subsciptions

* start subscription

* implementation for member done

* admin done

* fix: tests

* extend handlers

* prepary notification

* no errors in adminapi

* changed current sequence in all packages

* ignore mocks

* works

* subscriptions as singleton

* tests

* refactor: rename function scope var

internal/view/model/view.go

@@ -10,4 +10,5 @@ type View struct {
 	CurrentSequence          uint64
 	EventTimestamp           time.Time
 	LastSuccessfulSpoolerRun time.Time
+	AggregateType            string
 }