VOL-3705 Create option in kafka-topic-export to report ONU serial no in metrics in Hex format instead of ASCII chars

Change-Id: Id54f729efe4f9fee2accb3b18e97328b5e5db1ca
diff --git a/config/conf.yaml b/config/conf.yaml
index 4e299aa..d3c048e 100644
--- a/config/conf.yaml
+++ b/config/conf.yaml
@@ -18,3 +18,5 @@
   name: http-server
   port: 8080
   description: http target for prometheus
+conv:
+  onusnhex: false