Use the environment auto-stop feature
In %12.8, the environment auto-stop feature was released: https://docs.gitlab.com/ee/ci/environments.html#environments-auto-stop.
We should try it and set it to 2 days.
Also, since people can now pin environment if they need it for a longer time:
This pin-mark button can be used to prevent auto-stopping the environment. By clicking this button, the auto_stop_in setting is over-written and the environment will be active until it’s stopped manually
We can probably change the auto-cleanup that's done in scheduled master
pipelines to clean up Review Apps after something like 7 days instead?