Add boolean for applying changes only during maintenance window in order to not affect workloads during peak periods.

E.g.: we want to modify the instance type of our cluster, but we don't want to affect workloads during the day, therefore, any change to the cluster should be applied only during maintenance hours. The same functionality should be available in the console. As a matter of fact, all changes should be by default applied during maintenance window and user can choose to opt out and apply them immediately.

See DocumentDB as an example for this feature.
https://docs.aws.amazon.com/documentdb/latest/developerguide/db-instance-modify.html