feat: add systemd unit/timer files

misc/systemd/sentry-backup.service

@@ -0,0 +1,13 @@
+[Unit]
+Description=Sentry backup
+After=docker.service
+ 
+[Service]
+Type=oneshot
+WorkingDirectory=/mnt/data/backup
+ExecStartPre=/bin/sh -c 'systemctl -q is-active sentry.service && systemctl stop sentry'
+ExecStart=/opt/sentry-util/sentry-util.sh backup
+ExecStartPost=/bin/sh -c 'systemctl start sentry'
+
+[Install]
+WantedBy=multi-user.target

misc/systemd/sentry-backup.timer

@@ -0,0 +1,8 @@
+[Unit]
+Description=Timer for Sentry backup
+
+[Timer]
+OnCalendar=Mon 6:00:00
+
+[Install]
+WantedBy=multi-user.target