Support for cron

[jokay]

Is your feature request related to a problem? Please describe.

Not a problem, but some people may prefer using cron over an interval.

Describe the solution you'd like

Support for the default cronjobs by environment parameter.

# do daily/weekly/monthly maintenance
# min	hour	day	month	weekday	command
*/15	*	*	*	*	run-parts /etc/periodic/15min
0	*	*	*	*	run-parts /etc/periodic/hourly
0	2	*	*	*	run-parts /etc/periodic/daily
0	3	*	*	6	run-parts /etc/periodic/weekly
0	5	1	*	*	run-parts /etc/periodic/monthly

e.g. CRON={15min|hourly|daily|weekly|monthly}

Describe alternatives you've considered

None.

Additional context

• Running cron jobs in a Docker Alpine container