[Umbrella] grafana support with inference engines

[kerthcet]

What would you like to be added:

Install the grafana dashboard for inference engines:

• vllm: https://docs.vllm.ai/en/latest/getting_started/examples/prometheus_grafana.html
• sglang: https://github.com/sgl-project/sglang/tree/main/examples/monitoring
• llama.cpp
• TGI

Why is this needed:

Completion requirements:

This enhancement requires the following artifacts:

• Design doc
• API change
• Docs update

The artifacts should be linked in subsequent comments.

[kerthcet]

/help