[VOL-1615] Create VOLTHA 2.0 Helm Charts

Squashed version of David Bainbridge's patches at commit:

 https://github.com/ciena/voltha-helm-charts/commit/120fb4b719e0492e6a0a24cc78d08b806e3698fa

Linted the README, fixed whitespace and incubator repo address

Change-Id: I7c5b1c3478450bbefbed09a75e9029e6371cae3a
diff --git a/voltha-etcd-cluster/templates/etcd-cluster-service.yaml b/voltha-etcd-cluster/templates/etcd-cluster-service.yaml
new file mode 100644
index 0000000..08f294e
--- /dev/null
+++ b/voltha-etcd-cluster/templates/etcd-cluster-service.yaml
@@ -0,0 +1,30 @@
+{{- if .Values.etcdNodePort -}}
+---
+# Copyright 2017-present Open Networking Foundation
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+apiVersion: v1
+kind: Service
+metadata:
+  name: {{ .Values.clusterName }}-external
+spec:
+  type: NodePort
+  ports:
+    - port: 2379
+      targetPort: 2379
+      nodePort: {{ .Values.etcdNodePort }}
+      protocol: TCP
+  selector:
+    app: "etcd"
+{{- end -}}