Containerise web app for easier management, development and portability

[PaulHancock]

Maintaining and testing the web app is currently a little difficult, especially for non experts, as there is a lot of components/services that need to work together. As a result the documentation for installing, starting, restarting, and managing the web app is very long and full of technical details. If we were to instead bundle everything into a set of containers and then use docker-compose to manage these containers/services, then the app would be much easier to manage, and the documentation could be reduced and simplified significantly. Additionally, a dockerised web-app is much easier to build and test locally, meaning that fewer un-tested features need to be deployed on the live system.