Use scheduled action instead of lambda for autoscale-time

[ajliv]

Since Fargate now supports event based scheduling -- https://aws.amazon.com/about-aws/whats-new/2018/08/aws-fargate-now-supports-time-and-event-based-task-scheduling/

[awlawl]

I ran the template and also made sure that it would be modular enough to have either, both or neither of the scaling features and it works.

Thanks!

[abarfoot]

A quick review of the envvars of several deployments of the lambda indicates that its slack_webhook feature is not much used [good].

$ profiles='
> aws-corp-prod:aws-corp-prod-admin
> aws-digital-prod:aws-digital-prod-admin
> aws-ent-prod:aws-ent-prod-admin
> aws-news-prod:aws-news-prod-admin
> aws-shared-services:aws-shared-services-admin
> aws-sports-prod:aws-sports-prod-admin
> mpto:aws-mpto-admin
> '

$ for p in $profiles; do echo $p $(aws --profile "$p" lambda list-functions | grep slack_webhook | sort -u); done
aws-corp-prod:aws-corp-prod-admin "slack_webhook": ""
aws-digital-prod:aws-digital-prod-admin
aws-ent-prod:aws-ent-prod-admin "slack_webhook": ""
aws-news-prod:aws-news-prod-admin "slack_webhook": ""
aws-shared-services:aws-shared-services-admin "slack_webhook": ""
aws-sports-prod:aws-sports-prod-admin
mpto:aws-mpto-admin "slack_webhook": ""