allow for configurable openstack storage class

roles/kubernetes-apps/persistent_volumes/openstack/templates/openstack-storage-class.yml.j2

@@ -0,0 +1,14 @@
+{% for class in storage_classes %}
+---
+kind: StorageClass
+apiVersion: storage.k8s.io/v1
+metadata:
+  name: "{{ class.name }}"
+  annotations:
+    storageclass.kubernetes.io/is-default-class: "{{ class.is_default | default(false) }}"
+provisioner: kubernetes.io/cinder
+parameters:
+{% for key, value in (class.parameters | default({})).items() %}
+  "{{ key }}": "{{ value }}"
+{% endfor %}
+{% endfor %}