Generating models without any paths defined

[atombender]

I have a desire to generate model structs only, i.e. use this as a basic JSON Schema generator. As far as I can see, Ogen will not generate types for type definitions that aren't used in the paths. So if you have a schema with no paths defined, no model types will be generated.

While I can see that this isn't the primary use case with Ogen, supporting this use case would mean not having to reach out to another tool to accomplish it.