Adding Dockerfile and scripts for building and starting

[Paladinium]

A PR for a first draft of docker as discussed in #378

A few notes:

• Not sure whether it works on Windows
• Not sure whether it works just with CPUs
• A readme MD was added. This is to work on the documentation until Docker turns out to be stable enough to move the docs to your wiki. For the time being, I would appreciate to keep the MD file.
• Did not have time to check whether gradio works 100%. Please: let this PR pass and I will have a look into it in case there are issues.
• There are some warnings at the startup of the container -> fix later
• The image is not yet hardened. This means that the python application probably runs as root, which is a no-go for usage in production environments -> fix later