Only sync ntp once per week, sync to hardware clock

programs/ntp-rclocal/ntp.start

@@ -0,0 +1,8 @@
+#!/bin/sh
+old_timestamp="$(</etc/local.d/.ntpsync)"
+new_timestamp="$(date +%s)"
+if [ "$((new_timestamp-old_timestamp))" -gt 604800 ]; then
+    ntpdate -b pool.ntp.org
+    hwclock --systohc --utc
+    echo "$new_timestamp" > /etc/local.d/.ntpsync
+fi