Use jsoniter-scala instead of json4s for better efficiency

[plokhotnyuk]

You can run faster and save more energy using jsoniter-scala.

Here is a report that includes results of benchmarks for json4s and jsoniter-scala on different JVMs using different data types and real-world message samples.

The jsoniter-scala is quite competitive with binary parsers for Java/Scala: dkomanov/scala-serialization#8