Scheduled Actions

[eytan-avisror]

It would make a nice feature to allow changing scaling according to a cron expression.
AWS has a feature for scheduled actions, however this will most likely cause a ping-pong situation with the controller, since it's own definition of min/max will be different when the schedule kicks in.
https://docs.aws.amazon.com/sdk-for-go/api/service/autoscaling/#AutoScaling.PutScheduledUpdateGroupAction

We should evaluate our own implementation of scheduled actions, which will simply modify the min/max on given schedules.

If we have our own implementations, we can also scheduled other activities, such as node rotations, etc.