Add systemd .service file
Of note, the udevmon.yaml file has been shifted from the typical /etc/udevmon.yaml to /etc/interception.yaml. This is because the udevmon binary seems to be hardcoded to look for /etc/interception/udevmon.d/* for configuration files. It therefore makes more sense to have the main configuration file reside in /etc/interception/udevmon.yaml.
Fixes #27 (closed)