Currently, scala.Serdes.String, for example, invokes Serdes.String() once and caches the result.
However, the implementation of the String serde has a non-empty configure method that is variant in whether it's used as a key or value serde. So we won't get correct execution if we create one serde and use it for both keys and values.
Reviewers: Bill Bejeck <bill@confluent.io>, Guozhang Wang <wangguoz@gmail.com>