This removes our hardcoded presets which weren't updated for quite some time.
Infinality now has new hardcoded presets in freetype, which can be overriden if
desired with environment variables (as before). Accordingly, updated NixOS
module to set the hardcoded preset.
Additionally used a more "right" type for substitutions.
The name gitlab-runner clashes with a component of Gitlab CI with the
same name and only confuses people. It's now called gitlab-bundle and
a convenience-script gitlab-rake for easier invocation of rake tasks
was added. This was the primary use case of gitlab-runner.
