[Go schema] Support multi version schema for repo

Currently, we already support a single topic schema in producer and consumer for Go client.

The following are other functions of the schema that need to be supported:

- [ ] Support schema in reader
- [ ] Support multi version schema for Go client
- [ ] Support Key-Value schema
- [ ] Support auto schema

Start by reading the existing single-topic schema support in the Go producer and consumer. The issue lists reader schemas, multi-version schemas, key-value schemas, and auto schemas, but names no files or tests. Done would require defining and implementing the requested schema capabilities, with each checklist item covered by validation or tests.

Written by the indexing model from the issue text.