Add request/response logging in OpenAiApi

[markpollack]

For the chat models and the embedding models that are in OpenAiApi add logging at the debug level.

This should also be done for streaming endpoints using the technique in PromptChatMemoryAdvisor, e.g.

    @Override
    public Flux<ChatResponse> adviseResponse(Flux<ChatResponse> fluxChatResponse, Map<String, Object> context) {

        return new MessageAggregator().aggregate(fluxChatResponse, chatResponse -> {
            List<Message> assistantMessages = chatResponse.getResults()
                .stream()
                .map(g -> (Message) g.getOutput())
                .toList();

            this.getChatMemoryStore().add(this.doGetConversationId(context), assistantMessages);
        });
    }

[ThomasVitale]

I shared some thoughts about this in https://github.com/spring-projects/spring-ai/issues/512#issuecomment-2185096414