BiDiKo: Validate `*-reply` events (SET) created by zustelldienst again SET schema

The zustelldienst creates *-reply events here. These reply-* events should be valid with the SET-payload schema. To ensure these schemas are fulfilled, validate each *-reply event against it.

This ticket only covers newly introduced -*reply events. In a later step also *-submission events created by zustelldienst should be validated. See issue #1306 (closed).

Hint

The Java SDK already has a solution to verify events. This solution can be adopted in zustelldienst.

Akzeptanzkriterien

1. zustelldienst cannot create invalid *-reply events.

Durchführungsplan (von Entwickler:in bei Umsetzungsplanung auszufüllen)

• Analyse solution of Java SDK.
• adopt the solution in zustelldienst.