Reducing duplicated values on values files for SiaB

Reduced the amount of duplicated values between seba-ponsim values file.
To deploy, for example, the latest of seba-ponsim, now both seba-ponsim.yaml and seba-pomsim-latest.yaml values files need to be used with the specified order.
Makefile for SiaB is modified accordingly in the patch https://gerrit.opencord.org/#/c/16743/.
Also:
- removed stratumEnabled value from Mininet chart and added mnStratumSwitchCount
- moved bngAppUrl and bngAppVersion values on root of values file

Change-Id: I26b8e91f868646adc06f2c1feea72b333defd487
diff --git a/xos-profiles/seba-services/templates/_tosca.tpl b/xos-profiles/seba-services/templates/_tosca.tpl
index cb4a8e8..922fbc6 100644
--- a/xos-profiles/seba-services/templates/_tosca.tpl
+++ b/xos-profiles/seba-services/templates/_tosca.tpl
@@ -178,10 +178,10 @@
     onos_app#bng:
       type: tosca.nodes.ONOSApp
       properties:
-        name: {{ .bng.embedded.bngAppId }}
-        app_id: {{ .bng.embedded.bngAppId }}
-        url: {{ .bng.embedded.bngAppUrl }}
-        version: {{ .bng.embedded.bngAppVersion }}
+        name: org.opencord.bng
+        app_id: org.opencord.bng
+        url: {{ .bngAppUrl }}
+        version: {{ .bngAppVersion }}
         dependencies: {{ .fabric.stratum.pipeconfAppId }}, org.opencord.kafka, org.opencord.sadis
       requirements:
         - owner: