Enable Batch Inferencing Benchmarking Support

[rgreenberg1]

Purpose:
The purpose of this ticket is to support batch inference requests for GuideLLM. We will need to add in a batch-size parameter to enable the user to dictate the batch size of inference requests.

We will want to add non-streaming batched inferencing like this PR from llm-load-test openshift-psap/llm-load-test#66

Acceptance Criteria:

• Add a batch-size parameter in for the user to dictate the batch size of inference requests
• This should be non-streaming batching
• Once set, send requests in batches as dictated by the parameter
  Example:
  --batch-size=16, --batch-size=32