[Feature Request] Record server config from /server_info endpoint when vLLM 0.9.0 lands

[thameem-abbas]

If we can record the server config as part of the benchmark data via this endpoint, this would make life a whole lot easier to compare across runs.
The feature implementation for this would also require to check for the availability for the endpoint considering this is an optional endpoint.

Reference to the vLLM issue : vllm-project/vllm#16572