Separate build settings from defaults

Ghost User
2019-09-04T14:20:24+02:00

Currently we depend on `django_template_check` for the build, as it runs a test we would like to run during CI. This application provides a management command when installed. However, this means that it is installed in production (and development) environments as well, needlessly cluttering `requirements.txt` and `INSTALLED_APPS`. This may be a more general problem that can be fixed by re-thinking the way we manage settings (without introducing duplication).