VOL-642: Installation of VOLT-HA in a Kubernetes cluster

- Changed existing installer to support swarm and kubernetes
- Using kubespray as the base framework to deploy kubernetes
- Implemented config/deploy/teardown tasks for voltha

Amendments:

- Changed from python to python3 when running the inventory builder

Change-Id: I059fd348b9a749397b373e333b5602944c817745
diff --git a/k8s/zookeeper.yml b/k8s/zookeeper.yml
index 2f3ceba..112a460 100644
--- a/k8s/zookeeper.yml
+++ b/k8s/zookeeper.yml
@@ -66,6 +66,8 @@
 spec:
   serviceName: zoo1
   replicas: 1
+  updateStrategy:
+    type: RollingUpdate
   selector:
     matchLabels:
       app: zookeeper-1
@@ -104,6 +106,8 @@
 spec:
   serviceName: zoo2
   replicas: 1
+  updateStrategy:
+    type: RollingUpdate
   selector:
     matchLabels:
       app: zookeeper-2
@@ -142,6 +146,8 @@
 spec:
   serviceName: zoo3
   replicas: 1
+  updateStrategy:
+    type: RollingUpdate
   selector:
     matchLabels:
       app: zookeeper-3