Refactoring in non-bash script (Python etc.)

[130s]

Not urgent nor important (at least at the moment) but some interests and related benefits have been mentioned as following, so opening a placeholder specifically for the choice of language. However, I might be duplicating yet another placeholders. If so please point me there.

• Porting industrial_ci to Python https://github.com/ros-industrial/industrial_ci/issues/196#issuecomment-319908510. In particular, non-bash makes sense for ROS2 support if we want to do that.
• sh, not bash https://github.com/ros-industrial/industrial_ci/issues/125

[mathias-luedtke]

First step: https://github.com/ros-industrial/industrial_ci/pull/717 I guess a full port does not make too much sense, but some of the heavier tasks could be delegated to Python scripts.