- Move installation code to build.sh
- Add Jenkins to `docker` group to enable access to docker.sock
- Fix installing Docker for wrong Debian version
- From now on use automated detection of Debian version
- Install fewer packages by now installing recommends
- Do a proper cleanup of helper packages and apt lists
- Use sudoers.d instead of appending to sudoers
Signed-off-by: Knut Ahlers <knut@ahlers.me>