Enable me to explore on Jupyterhub behind reverse proxy

I want to try out notebooker. I don't have access to python on my laptop for enterprise reasons. I can work inside jupyterhub.

I run

```
mkdir -p /home/jovyan/shared/.analytics-workspace/.mongodb
conda install -y -c anaconda mongodb=6.0.2
pip install notebooker;python -m ipykernel install --user --name=notebooker_kernel
````

```bash
mongod --dbpath /home/jovyan/shared/.analytics-workspace/.mongodb
```

```bash
notebooker-cli --mongo-host localhost:27017 start-webapp --port 11828
```

Both mongodb and notebooker start up successfully.

The [jupyter-server-proxy](https://github.com/jupyterhub/jupyter-server-proxy) is installed. So I would expect to be able to try out notebooker ui at

## https://domain/namespace/user/user-name/proxy/11828


or

## https://domain/namespace/user/user-name/proxy/11828/


But as you can see I cannot.

The issue is that all *assets* are expected to be found at the root `/`.


But they should not be. Either they should be found at some nested path that I should be able to specify via a `--prefix` flag. Or they should be referenced as `./static` I believe.

## Additional Context

I often run [Panel](https://panel.holoviz.org/index.html) succesfully from the terminal in my jupyter hub. Panel enables me to set a `--prefix` that is used to point to the static assets.


Its the same for other data app frameworks. For example streamlit.