Draft: Add a Dockerfile

Working with the colleagues from KDO we found that it would be nice to have a Dockerfile available to use the tooling from this repository for user import. This avoids the need of installing Python dependencies locally.

The MR is not yet fully ready. I faced issues with the dependency logging, installing it fails locally on my machine and also in the docker build. I am not sure if / why the dependency is needed and could use a hint on this.

TODO:

• Clarify if the dependency logging is required
• Add example how to use the container, e.g. docker run -v .:/data ... --import-file /data/my-file.ods ...
• Build image in pipeline