Packaging: Automated deployment via Gitlab CI

@lang-m and @fangohr Following on from issue #1041 (closed) opened by a user, it would be very useful to include a deployment step in the CI that creates a tarbell for Octopus following the bump of a major.minor.patch version number. As it currently stands, I don't know how @martin.lueders builds the package but this is something we could look to add during the Garching week.

We could test this by using a dummy version number and uploading an artefact. Or if we don't want to automate checking changes in version number, we could add deployment for any commit with a new git tag.

Additionally, we could also discuss deployment to dockerhub.