0021521: Extend system certificate tool for preferred certs

Migrated from: https://tracker.clearos.com/view.php?id=21521

Reported by: PBaldwin

The new system certificate tool provides a common way to deploy certificates to other apps. The tool provides either the "bootstrap certificates" (auto-generated with defaults) or - if available - the "system certificates" (created by administrator via webconfig).

Most apps only initialize just once and will accept either type of certificate. However, the OpenLDAP system for master/slave mode eventually needs to the "system certificates" when these become available. So the workflow is:

• OpenLDAP initializes with the bootstrap key
• When master/slave mode is enabled, the system certificate is required and deployed via an event

Tracker 0021511 needs this functionality added the system certificate tool.