XOS/NEM charts, use a global registry var, split docker image name/tag/pullPolicy

Change-Id: I7f3457882830de050d1357254fc5483faf91d03f
diff --git a/xos-services/openstack/values.yaml b/xos-services/openstack/values.yaml
index bf45148..e619da0 100644
--- a/xos-services/openstack/values.yaml
+++ b/xos-services/openstack/values.yaml
@@ -24,7 +24,13 @@
 
 imagePullPolicy: 'Always'
 
-openstack_synchronizerImage: "xosproject/openstack-synchronizer:{{ .Chart.Version }}"
+image:
+  repository: xosproject/openstack-synchronizer
+  tag: "{{ .Chart.AppVersion }}"
+  pullPolicy: Always
+
+global:
+  registry: ""
 
 xosAdminUser: "admin@opencord.org"
 xosAdminPassword: "letmein"