Add Docker and Kubernetes Support for GuideLLM Benchmarking

[wangchen615]

We need a dockerfile to enable running GuideLLM benchmarks in a containerized environment and as a Kubernetes job. This would be helpful for users who want to run benchmarks in a more controlled and scalable environment.

The first change should include:

Dockerfile

• Based on Python 3.11 slim image
• Installs GuideLLM and its dependencies
• Entrypoint to run benchmarks with environment variables