[feat] Add a CookieManager to the WebView

### Describe the problem

I need an API to get cookies from an external WebView

### Describe the solution you'd like

```ts
const webview = new WebviewWindow('theUniqueLabel', {
  url: 'https://tauri.app/',
});
const allCookie = await webview.cookieManager.getAllCookie();
// ...
```

### Alternatives considered

_No response_

### Additional context

_No response_