fix: User checks (#139)

* check uniqueness on create and register user

* change user email, reserve release unique email

* usergrant unique aggregate

* usergrant uniqueness

* validate UserGrant

* fix tests

internal/notification/repository/eventsourcing/handler/notify_user.go

@@ -52,7 +52,7 @@ func (p *NotifyUser) Process(event *models.Event) (err error) {
 			return err
 		}
 		err = user.AppendEvent(event)
-	case es_model.UserDeleted:
+	case es_model.UserRemoved:
 		err = p.view.DeleteNotifyUser(event.AggregateID, event.Sequence)
 	default:
 		return p.view.ProcessedNotifyUserSequence(event.Sequence)