chore: move benchmarking related code (#3406)

# What does this PR do?
- moving things and some formatting changes


## Test Plan

docs/source/distributions/k8s-benchmark/stack-k8s.yaml.template

@@ -1,83 +0,0 @@
-apiVersion: v1
-kind: PersistentVolumeClaim
-metadata:
-  name: llama-benchmark-pvc
-spec:
-  accessModes:
-    - ReadWriteOnce
-  resources:
-    requests:
-      storage: 1Gi
----
-apiVersion: apps/v1
-kind: Deployment
-metadata:
-  name: llama-stack-benchmark-server
-spec:
-  replicas: 1
-  selector:
-    matchLabels:
-      app.kubernetes.io/name: llama-stack-benchmark
-      app.kubernetes.io/component: server
-  template:
-    metadata:
-      labels:
-        app.kubernetes.io/name: llama-stack-benchmark
-        app.kubernetes.io/component: server
-    spec:
-      containers:
-      - name: llama-stack-benchmark
-        image: llamastack/distribution-starter:latest
-        imagePullPolicy: Always # since we have specified latest instead of a version
-        env:
-        - name: ENABLE_CHROMADB
-          value: "true"
-        - name: CHROMADB_URL
-          value: http://chromadb.default.svc.cluster.local:6000
-        - name: POSTGRES_HOST
-          value: postgres-server.default.svc.cluster.local
-        - name: POSTGRES_PORT
-          value: "5432"
-        - name: INFERENCE_MODEL
-          value: "${INFERENCE_MODEL}"
-        - name: SAFETY_MODEL
-          value: "${SAFETY_MODEL}"
-        - name: TAVILY_SEARCH_API_KEY
-          value: "${TAVILY_SEARCH_API_KEY}"
-        - name: VLLM_URL
-          value: http://vllm-server.default.svc.cluster.local:8000/v1
-        - name: VLLM_MAX_TOKENS
-          value: "3072"
-        - name: VLLM_SAFETY_URL
-          value: http://vllm-server-safety.default.svc.cluster.local:8001/v1
-        - name: VLLM_TLS_VERIFY
-          value: "false"
-        command: ["python", "-m", "llama_stack.core.server.server", "/etc/config/stack_run_config.yaml", "--port", "8323"]
-        ports:
-          - containerPort: 8323
-        volumeMounts:
-          - name: llama-storage
-            mountPath: /root/.llama
-          - name: llama-config
-            mountPath: /etc/config
-      volumes:
-      - name: llama-storage
-        persistentVolumeClaim:
-          claimName: llama-benchmark-pvc
-      - name: llama-config
-        configMap:
-          name: llama-stack-config
----
-apiVersion: v1
-kind: Service
-metadata:
-  name: llama-stack-benchmark-service
-spec:
-  selector:
-    app.kubernetes.io/name: llama-stack-benchmark
-    app.kubernetes.io/component: server
-  ports:
-  - name: http
-    port: 8323
-    targetPort: 8323
-  type: ClusterIP