Milestone ProvisioningService: Add monitoring support

The Raven tool suite now includes a prototype of "Owl", a service that monitors activities within a slice. Owl includes a daemon that runs in the slice and periodically runs a set of scripts that collect information about the internals of the slice. This information is sent to an Owl server that stores it in a MySQL database and makes it available for viewing and download via HTTP. The set of scripts that Owl runs and the information that it collects are highly configurable, allowing Owl to monitor a wide variety of user-specified activities. Owl is currently used to monitor the health of Stork, Pacman, and Owl itself. Owl was demonstrated at GEC5.