Added systemd file to start java app instead of using rc.local

raspberrypi_monitor.service

+[Unit]
+Description=Manage raspberrypi monitor service
+
+[Service]
+WorkingDirectory=/var/log
+ExecStart=/usr/bin/java -jar /root/janipi/target/raspberrypi.janipi-0.0.1-SNAPSHOT.jar
+User=root
+Type=simple
+Restart=on-failure
+RestartSec=10
+
+[Install]
+WantedBy=multi-user.target