Create a release workflow

[mnonnenmacher]

Create a release workflow that is triggered by pushing a new version tag, similar to the release workflow from ORT. The workflow should perform the following tasks:

• Publish the Docker images (this does not necessarily have to happen in the same workflow, it could also be handled by the existing Docker build workflow).
• Publish artifacts to Maven Central (Publish (some of) the project's JARs to Maven Central #803).
• Publish the documentation (Publish the documentation on GitHub pages #881).
• Create a release on GitHub.