metrics: Add cassandra service yaml

This PR adds the cassandra service yaml for the benchmark.

Signed-off-by: Gabriela Cervantes <gabriela.cervantes.tellez@intel.com>

tests/metrics/disk/cassandra_kubernetes/volume/runtimeclass_workloads/cassandra-service.yaml

@@ -0,0 +1,17 @@
+#
+# Copyright (c) 2022-2023 Intel Corporation
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+apiVersion: v1
+kind: Service
+metadata:
+  labels:
+    app: cassandra
+  name: cassandra
+spec:
+  clusterIP: None
+  ports:
+  - port: 9042
+  selector:
+    app: cassandra