Bug 1115146 - Purge (delete) data using smaller batches

Introduced JDBCPurgeTemplate

Update purge process for:
* availabilities
* traits
* events
* calltime data values
* alerts (and notif log and condition log)
* OOB

Batch size:
* is shared across implementation of the template
* is configurable through a sys prop
* value is unbounded
* defaults to 3000