Add support for OpenAI "Developer Messages" introduced in openAI java client 0.8 #532
Description
While implementing #531, I discoveres that openAI added developer messages as replacement for system messages.
We'll need to decide on how to handle them, because currently the semantic conventions don't cover those.
At the moment the instrumentation will fail if event logging is enabled, because it encounteres an unknown type.
Some possible alternatives:
- Don't report as an event and wait for semconv
- Report as system.message for now