[VOL-3091] configurable kafka topic

Make core-topic and adapter topics configurable in voltha-helm-charts
This is required to run multiple voltha stacks in a k8s deployment.

Also, read the kv_store_data_prefix via environment variable.
https://gerrit.opencord.org/#/c/19001/

Change-Id: I8fabda3ce70f1379f735796e6711f4282e57008a
diff --git a/voltha-adapter-openonu/templates/adapters-openonu.yaml b/voltha-adapter-openonu/templates/adapters-openonu.yaml
index feb5666..f7ffa94 100644
--- a/voltha-adapter-openonu/templates/adapters-openonu.yaml
+++ b/voltha-adapter-openonu/templates/adapters-openonu.yaml
@@ -71,8 +71,9 @@
           - "REPLICA_ID=$(echo $VOLTHA_POD_NAME | grep -o '.$') && REPLICA_ID=$((REPLICA_ID + 1)) && echo $REPLICA_ID && python /voltha/adapters/brcm_openomci_onu/main.py
               --kafka_adapter={{ .Values.services.kafka.adapter.service }}:{{ .Values.services.kafka.adapter.port }}
               --kafka_cluster={{ .Values.services.kafka.cluster.service }}:{{ .Values.services.kafka.cluster.port }}
-              --core_topic=rwcore
-              --name=brcm_openomci_onu
+              --core_topic={{ .Values.defaults.topics.core_topic }}
+              --adapter_topic={{ .Values.defaults.topics.adapter_open_olt_topic }}
+              --name={{ .Values.defaults.topics.adapter_open_onu_topic }}
               --backend=etcd
               --etcd={{ .Values.services.etcd.service }}:{{ .Values.services.etcd.port }}
               --probe=:8080