[CP-6209] Add the lite guest aganet to the xeniface build

Adds a new lite agent project to the xeniface solution

This removes most of the functionality which was present in the non-building stub agent code, leaving just the time setting code (as part of a suspend handler) and the shutdown/reboot code

The WMI code has been modifed to better report failures, and the service code hardened to recover in the event of WMI going away (or not being present at start of day)

The new agent is set to install as a userland service winthin the xeniface .inf file