DCM Maintenance App - ErrorExchange added

Dead letter messages that are not supported will now be sent to an errorExchange including queue. These messages will remain there until a maintainer does something with them.

This change is added to prevent infinite loops in the maintenance app. Beacuse of this change the following steps are needed to do.

In the blueriq-dcm-maintenance-app.yml file, an ErrorExchange needs to be added for the dead letter functionality.

blueriq:
  ....
  dcm:
    maintenance:
      app:
        dlq:
          rabbitmq:
            queueNames:
              ....
            errorExchange: dlx.dcmMaintenanceApp

In RabbitMQ, define the errorExchange, dead letter queue and a binding between them. Keep in mind that the errorExchange name needs to be the same as in the configuration of the maintenance app. By default the errorExchange is defined as dlx.dcmMaintenanceApp in the blueriq-dcm-maintenance-app.yml.