update appVersions for all charts before release

* update and clean up appVersions for all voltha related charts to
  included latest software/application releases into next voltha release
* update voltha-stack chart to include new chart versions
* make sure all voltha-* charts have at minimal a 2.12.X version to
  point out their relation to the upcoming voltha-2.12 release and avoid
  version collision with previously developed and published chart
  versions from voltha-2.X branches
* the charts voltha-go-controller and voltha-northbound-bbf-adapter are
  currently still under development and the chart versions have
  therefore not been increased to align with the voltha 2.12 release
  naming scheme described above
* application version updates:
  * bbsim-sadis-server from 0.3.4 to 0.3.5
  * voltha-adapter-openonu from 2.7.3 to 2.11.3
  * voltha-adapter-openolt from 4.3.6 to 4.4.5
  * voltha-tracing (jaeger) from 1.18 to 1.51
  * voltha-ofagent-go from 2.1.3 to 2.1.6
  * voltha-rw-core from 3.1.8 to 3.4.8
* update some comments for appVersion in Chart.yaml files to be more
  precise about how this value is used

Change-Id: I04879ecf822b6cac5d9d55fbab6a86efc11ae55d
Signed-off-by: Jan Klare <jan.klare@bisdn.de>
diff --git a/voltha/values.yaml b/voltha/values.yaml
index 319bab8..7a601e3 100644
--- a/voltha/values.yaml
+++ b/voltha/values.yaml
@@ -105,17 +105,19 @@
   kv_store_data_prefix: 'service/{{ .Values.global.stack_name }}_voltha'
 
 # Define Docker images to be used
+# voltha-ofagent-go repo https://github.com/opencord/ofagent-go
+# voltha-rw-core repo https://github.com/opencord/voltha-go
 images:
   ofagent:
     registry: '{{ .Values.global.image_registry }}'
     repository: '{{ .Values.global.image_org }}voltha-ofagent-go'
-    tag: '{{- if hasKey .Values.global "image_tag" }}{{- if .Values.global.image_tag }}{{ .Values.global.image_tag }}{{- else }}2.1.3{{- end }}{{- else }}2.1.3{{- end }}'
+    tag: '{{- if hasKey .Values.global "image_tag" }}{{- if .Values.global.image_tag }}{{ .Values.global.image_tag }}{{- else }}2.1.6{{- end }}{{- else }}2.1.6{{- end }}'
     pullPolicy: '{{ .Values.global.image_pullPolicy }}'
 
   rw_core:
     registry: '{{ .Values.global.image_registry }}'
     repository: '{{ .Values.global.image_org }}voltha-rw-core'
-    tag: '{{- if hasKey .Values.global "image_tag" }}{{- if .Values.global.image_tag }}{{ .Values.global.image_tag }}{{- else }}3.1.8{{- end }}{{- else }}3.1.8{{- end }}'
+    tag: '{{- if hasKey .Values.global "image_tag" }}{{- if .Values.global.image_tag }}{{ .Values.global.image_tag }}{{- else }}3.4.8{{- end }}{{- else }}3.4.8{{- end }}'
     pullPolicy: '{{ .Values.global.image_pullPolicy }}'
 
 ingress: