Make a Dockerfile to run Studio-Web locally in a docker image

[joanise]

The image needs to run Studio/readalongs/web_api.py in our process and serve this app in another. It should expose a port so we can connect to it from a browser on the host computer rather than inside the image.

Useful references for running more than one process in a Docker image, although I'm sure there are many more ways to do it:

• https://stackoverflow.com/questions/57169267/how-to-run-two-commands-on-dockerfile
• https://riptutorial.com/docker/example/14132/dockerfile-plus-supervisord-conf
• http://supervisord.org/