feat: add cron for flushing disk cache

# disable swap

@reboot swapoff -a

{% if type == 'vm' %}

# flush caches every 2 hours

0       */2     *       *       *       echo 3 > /proc/sys/vm/drop_caches

{% endif %}

# update packages between 3:15-3:30 am

15      3       *       *       *       sleep $(($RANDOM % 900)) && apk -U upgrade >/dev/null 2>&1 && apk clean cache && reboot -d 60