Work Item Set Purge batch process

Code	`WorkItemSetPurge`
Categories	`UIRunnable`, `Schedulable`
Implementation	Batch process
Stoppable	No (single phase process)
Schedule	On the second day of the month, at 1:30 a.m.
Class	WorkItemSetPurge.gs

The Work Item Set Purge batch process purges work item sets from the database. This process uses Gosu class WorkItemSetPurge to read the value of the BatchProcessHistoryPurgeDaysOld parameter in config.xml. The process then uses this value to determine the number of days to retain work item sets before purging them.

Note: The BatchProcessHistoryPurgeDaysOld parameter also configures how many days to retain process history records, which the separate Process History Purge batch process process removes.