Add demo installation with Docker image

[stweil]

A Docker image of PalMA could be used for demos and test, but also to add PalMA functionality to simple presentation PCs.

[wagneral]

No actions since may 2017: therefore closed.

[stweil]

I'd like to keep that open.

[jmechnich]

A Dockerfile has been added with tag v1.4.8.
A Docker image can be built and run on the fly e.g. with docker run -it -e THEME=ub-mannheim/a3 -h palma-docker --name palma --rm $(docker build -q github.com/UB-Mannheim/PalMA.git).

[dennmuel]

In the latest version (using chromium on bullseye) an additional flag --cap-add=ALL is needed:

docker run -it -e THEME=ub-mannheim/a3 -h palma-docker --name palma --rm --cap-add=ALL $(docker build -q github.com/UB-Mannheim/PalMA.git)