This task removes entries in the source journal global that are older
than the configured value.
It is normally run nightly.
This defines the user-visible name of this task. It is defined in the subclasses.
Default purge of 2 months
Validate KeepDays value method OnTask() as %Status
This method is responsible for executing the task.
At the scheduled time, the Task Manager creates an instance of this object, sets any property values using the stored "settings" for the task, and then invokes this method to execute the task.