The system-global path of
/etc/jenkins_jobs/jenkins_jobs.ini
is not applicable on Windows. To solve that, and as Linux users would
benefit from a per-user configuration file, too, introduce a fallback at
~/.config/jenkins_jobs/jenkins_jobs.ini
following the XDG Base Directory Specification. Try to use that per-user
file if no configuration file is given on the command line and none is
present in the script directory for development purposes.
Change-Id: I1a22454999ee8ac60d6f22545850c33aa03bb29b