[Feature] Expose SQLite-backed Synchronous KV API for Durable Objects

### Is there an existing issue for this? - [x] I have searched the existing issues ### Description Durable Objects provide a [Synchronous KV API](https://developers.cloudflare.com/durable-objects/api/sqlite-storage-api/#synchronous-kv-api) on top of SQLite-backed storage. However, the Rust `worker` crate only exposes the [asynchronous API](https://docs.rs/worker/latest/worker/durable/struct.Storage.html). ### Request Expose the Synchronous KV API in Rust for parity with the JavaScript runtime.