[Task]: Implement JsonUtils #22768
Description
What needs to happen?
The output of this task is to create org.apache.beam.sdk.schemas.utils.JsonUtils.
The purpose is to have a central place for helper methods to convert to and from Json encoding in the setting of schema-aware PCollections.
The design will pattern similar but not exactly as AvroUtils in the same package.
Issue Priority
Priority: 2
Issue Component
Component: sdk-java-core