Explore modernising the user & admin application Spawner

[flongford]

A similar project provides a Jupyter extension to create desktop sessions in a browser via noVNC.

https://github.com/jupyterhub/jupyter-remote-desktop-proxy

In this setup, the jupyter/base-notebook image is used as a base image, and the noVNC components are built on top. Presumably the JupyterHub server is then configured with the DockerSpawner, which was not widely available when the Simphony-Remote project began.

We might benefit from exploring whether we could try a similar spawner design in replacement of the VirtualUserSpawner. However, we'll likely run into Docker-in-Docker complexities, since the SR applications themselves are already containerised, so some prototyping will be beneficial.