[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.