Scheduled Commands (cron jobs) are too limited

[timkelty]

Crons are currently limited to a granularity of 1 hr and a limit of 5 per environment.
Both restrictions can be too limiting for some projects.

Related: #56

For @jamesmacwhite :)

[angrybrad]

This has been changed to 15 minutes and 10 per environment now.

[jamesmacwhite]

This is great news! Certainly more flexible. Not going to lie, we'd still burn through the 10, but we have a Cron Controller that triggers service logic in queue jobs and console commands, so it isn't a major issue. We can prioritise important cron jobs however with the native scheduler.