Add in cron_rand to the core filter plugins.

cron_rand generate random whole number(s) based on a seed for repeatable randomness. Each host will generate a different random number, but a specific host's result will not change between runs. This prevents thundering herd issues with resource intensive cron tasks. Seed is typically inventory_hostname or inventory_hostname combined with a string to prevent multiple cronjobs on a server from sharing the same offset.

This is something I really missed having from puppet and this is a nice expansion over their functionality with allowing multiple times per period.