Add Dockerfiles and Docker instructions

[Vidminas]

The main https://github.com/CommunitySolidServer/CommunitySolidServer repo has instructions for running with Docker. To make integrating the recipes easier into existing Docker workflows, I've added a minimal Dockerfile for each of the extensions and instructions how to use them.

I've only recently started using Docker, so a review of the Dockerfiles by someone with more experience might be helpful

[joachimvh]

Assigning @Falx to this as he handles everything docker related in the CSS repo. The docker files are missing a trailing newline though.