Make it possible to override serde config (#146)

Author: Rishabh

hypertrace-view-generator/hypertrace-view-generator/src/main/resources/configs/all-views/application.conf

@@ -20,4 +20,10 @@ kafka.streams.config = {
 
   schema.registry.url = "http://localhost:8081"
   schema.registry.url = ${?SCHEMA_REGISTRY_URL}
+
+  default.key.serde = "io.confluent.kafka.streams.serdes.avro.SpecificAvroSerde"
+  default.key.serde = ${?DEFAULT_KEY_SERDE}
+
+  default.value.serde = "io.confluent.kafka.streams.serdes.avro.SpecificAvroSerde"
+  default.value.serde = ${?DEFAULT_VALUE_SERDE}
 }