https://github.com/openai/codex/pull/642 introduced support for the `--disable-response-storage` flag, but if you are a ZDR customer, it is tedious to set this every time, so this PR makes it possible to set this once in `config.toml` and be done with it. Incidentally, this tidies things up such that now `init_codex()` takes only one parameter: `Config`.