fix puppet installation

Signed-off-by: Dominik Richter <dominik.richter@gmail.com>
added description for docker installation to readme

Signed-off-by: Dominik Richter <dominik.richter@gmail.com>
create a separate manifest for configuring docker

Signed-off-by: Dominik Richter <dominik.richter@gmail.com>
improvement: ignore exit codes during docker builds

as puppet react with non-zero exit codes on warnings, this may get in the way of building examples and debugging later on. always finish building the image to make it available

Signed-off-by: Dominik Richter <dominik.richter@gmail.com>