[Feature] Support allowConcurrency and noCache options for Durable Object get() function

### Is there an existing issue for this?

- [x] I have searched the existing issues

### Description

As described in https://developers.cloudflare.com/durable-objects/api/storage-api/#supported-options, it should be possible to submit a Durable Object `get()` request with the `allowConcurrency` and/or `noCache` options.

This _may_ already be possible today by calling https://github.com/cloudflare/workers-rs/blob/a16090aa737be88b1d647a7be319c5159b728c61/worker-sys/src/types/durable_object/namespace.rs#L39 directly. If so, we should document it and add an example.