System container installer

These files are needed to run the installer using an Atomic System container.

config.json.template - Template of the configuration file used for running containers.
manifest.json - Used to define various settings for the system container, such as the default values to use for the installation.
run-system-container.sh - Entrypoint to the container.
service.template - Template file for the systemd service.
tmpfiles.template - Template file for systemd-tmpfiles.