BiDiKo: Document new error codes introduced with BiDiKo

The feature BiDiKo introduced new error codes (example reply-not-found). These new error codes should be documented in the public documentation: https://docs.fitko.de/fit-connect/docs/status-and-error-codes/#liste-von-fehlercodes

Akzeptanzkriterien

1. Add new introduced (within the implementation of BiDiKo) error codes to the public documentation.

Durchführungsplan (von Entwickler:in bei Umsetzungsplanung auszufüllen)

• analyse which error codes where introduced with BiDiKo.
• Update documentation and add new error codes to it.