Adding yamllinter to ci steps (#1556)

* Adding yaml linter to ci check

* Minor linting fixes from yamllint

* Changing CI to install python pkgs from requirements.txt

- adding in a secondary requirements.txt for tests
- moving yamllint to tests requirements

roles/kubernetes-apps/ansible/templates/kubedns-autoscaler.yml.j2

@@ -0,0 +1,52 @@
+---
+# Copyright 2016 The Kubernetes Authors.
+#
+# 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: extensions/v1beta1
+kind: Deployment
+metadata:
+  name: kubedns-autoscaler
+  namespace: {{ system_namespace }}
+  labels:
+    k8s-app: kubedns-autoscaler
+    kubernetes.io/cluster-service: "true"
+    addonmanager.kubernetes.io/mode: Reconcile
+spec:
+  template:
+    metadata:
+      labels:
+        k8s-app: kubedns-autoscaler
+      annotations:
+        scheduler.alpha.kubernetes.io/critical-pod: ''
+        scheduler.alpha.kubernetes.io/tolerations: '[{"key":"CriticalAddonsOnly", "operator":"Exists"}]'
+    spec:
+      containers:
+      - name: autoscaler
+        image: "{{ kubednsautoscaler_image_repo }}:{{ kubednsautoscaler_image_tag }}"
+        resources:
+          requests:
+            cpu: "20m"
+            memory: "10Mi"
+        command:
+        - /cluster-proportional-autoscaler
+        - --namespace={{ system_namespace }}
+        - --configmap=kubedns-autoscaler
+        # Should keep target in sync with cluster/addons/dns/kubedns-controller.yaml.base
+        - --target=Deployment/kube-dns
+        - --default-params={"linear":{"nodesPerReplica":{{ kubedns_nodes_per_replica }},"min":{{ kubedns_min_replicas }}}}
+        - --logtostderr=true
+        - --v=2
+{% if rbac_enabled %}
+      serviceAccountName: cluster-proportional-autoscaler
+{% endif %}