OMCI capture option in openonu-go-adapter

We would like to have an option to capture OMCI traffic (for analysis).

Prior to VOLTHA 2.9 we used a method to capture the traffic on the Kafka-bus and decrypt the messages to receive an OMCI capture. But with VOLTHA 2.9 we are not able to easily intercept GRPC traffic and do the same.

Therefore we would like to have an option on the openonu-go-adapter to enable via a helm flag like --set omci-capture=true to save the OMCI into a file inside the openonu-go adapter container. This would help us a lot in debugging OMCI traffic (especially when testing different ONU/ONT models).

This is option is only intended to be used for testing - not for production as it would probably have some impact on the performance.