CI: Set a 4-day timer to auto stop review apps in GKE and EKS
Closes #2075 (closed)
Uses auto_stop_in to automatically stop review app environments after a given amount of time (in the case of this MR, 4 days).
Documentation on the feature is here: https://docs.gitlab.com/ee/ci/environments.html#environments-auto-stop
One important note from the documentation link is that the timer resets on each new commit. That way, actively developed MRs won't see their review apps taken down until 4 days of no pushed commits.
NOTE: As far as I can tell, this won't affect pre-existing environments. So we'll need to manually clean out any environments created prior to this change, and the rest will respect the auto-shutdown rule.
Screenshot from the environments page:
