This update for obs-service-kiwi_metainfo_helper fixes the following issues:

- Use a boolean dep to avoid use of %{is_opensuse}. The prjconf selects which one to use this way.
- Fix grammar, update README and .service.
- Also allow working on Chart.yaml. (jsc#CAPS-5)
- Add explicit fallback for chroot builds
- Refactor into a single sed call
- Also allow working on Dockerfile (jsc#CAPS-10)
- Strip service prefix from the recipe name to work with enabled services in OBS

This update was imported from the SUSE:SLE-15:Update update project.