Java client, adds responses

[spacether]

Java client, adds response object implementation which allows for de-serialization of responses

• schema sealed class changed to selaed interface to reduce qty of generated code
• schema implementing sealed classes now use records to reduce amount of generated code
• request bodies updated to use sealed interface and record classes to reduce amount of generated code
• responses use sealed interfaces for response bodies and media types

Future Work

• Implement a class that stores responses

PR checklist

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