Add Kotlin Serialization Support

[robertfmurdock]

Is your feature request related to a problem? Please describe.

For people who want to use the Kotlin codegeneration and also use Kotlin serialization, annotations need to be used. As is, only reflective kotlin parsing frameworks can be used.

Describe the solution you'd like

Add an option to the kotlin codegen that enables inclusion of these annotations.

Describe alternatives you've considered

The kotlin serialization plugin only offers generated serializers as an alternative to its own generated serializers, which would require substantially more code generation (and not be that great anyway).

Additional context

I'm a user of kotlin multiplatform, where kotlin serialization works but the Java-only JSON parsing choices do not, so it solves a problem for me.