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

Change-Id: I7f3457882830de050d1357254fc5483faf91d03f
diff --git a/sadis-server/values.yaml b/sadis-server/values.yaml
index f65a8bc..7c3cea9 100644
--- a/sadis-server/values.yaml
+++ b/sadis-server/values.yaml
@@ -12,8 +12,14 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-image: "opencord/sadis-server:latest"
-imagePullPolicy: Always
+
+image:
+  repository: 'opencord/sadis-server'
+  tag: '{{ .Chart.AppVersion }}'
+  pullPolicy: 'Always'
+
+global:
+  registry: ''
 
 xosAdminUser: "admin@opencord.org"
-xosAdminPassword: "letmein"
\ No newline at end of file
+xosAdminPassword: "letmein"