Docker image

Provide an up-to-date docker image for the latest version of GERBIL.

### User Story

As a user, I would like to get GERBIL as a Docker image. The image should:
1. be easy to start (i.e., in the best case, it comes with a `docker-compose ` file that I can execute easily),
2. allow the fine grained configuration that GERBIL offers through it's properties files,
3. persist the experiment data,
4. be able to work with and without local indexes and
5. should be kept up-to-date (i.e., it should be part of the building and publication process to build and publish a new Docker image).

No files or tests are named. Start by inspecting the existing build and publication process, then determine how GERBIL configuration, experiment data, and optional local indexes should be exposed in the image. Done means an up-to-date image is easy to start, supports those configuration and persistence requirements, and is built and published with releases.

Written by the indexing model from the issue text.