Support Producing JSON Schema

[hearnadam]

Producing a schema from a (derived) codec seems quite useful to ensure consistency across non-Scala stack. It can also be used to Prompt LLMs for consistent response format.

The schema could be output either as String or as a JSON AST.

https://json-schema.org/draft/2020-12/json-schema-core

[markschaake]

There is a similar issue in zio-schema: zio/zio-schema#189

From my current understanding, it seems like zio-schema would be the more natural place to do the to-json-schema implementation. The idea being that you derive first a Schema[Foo] and from that schema you derive both a JsonCodec[Foo] and a JsonSchema[Foo].

Is there a stronger reason to pack the to-json-schema into zio-json instead of handling in zio-schema?