Adding metrics handler

Author: courageJ

pkg/manifests/ext_proc.yaml

@@ -49,7 +49,6 @@ spec:
       containers:
       - name: inference-gateway-ext-proc
         # TODO(https://github.com/kubernetes-sigs/llm-instance-gateway/issues/34) Update the image and args.
-        image: us-central1-docker.pkg.dev/k8s-staging-images/llm-instance-gateway/epp:main
         args:
         - -serverPoolName 
         - "vllm-llama2-7b-pool"
@@ -59,7 +58,8 @@ spec:
         - "vllm-llama2-7b-pool"
         ports:
         - containerPort: 9002
-        
+        - name: metrics
+          containerPort: 9090
       - name: curl
         image: curlimages/curl
         command: ["sleep", "3600"]