Add Kubernetes and new env var docs

[solidDoWant]

Adds docs that cover both the new env vars for #110, and some example k8s deployments showing how these can be used.

Rendered doc is available here.

This still needs a few changes:

• Enable OpenVINO model caching #118 needs to land first
• There is a bug with the /status endpoint that needs to be resolved before probes can be added Fix transcribe Qwen3-ASR models blocking other API calls #127
• IMO at least some of the logic for these scripts should be moved to CLI commands. Ideally there would be a command to download, generate config for, and compile models (hf download + openarc add + openarc serve/load).