qtd3dservice: Support Appx device monitoring

Like Xap monitoring, local appx packages can be automatically monitored.
This is accomplished without polling by:
 - Waiting for changes in the package registry
 - Checking the list of developer apps from the Appx manager
 - Waiting for changes in the application's shader directory

Without polling, the service has 0% CPU utilization when idle, regardless
of the number of Appx packages monitored. This is compared to Xap devices,
which may incur several fractions of a percent of CPU time during
package polling.

Change-Id: I3b0fc6fc7a8beee854c2511295b6d33b102eee88
Reviewed-by: Oliver Wolff <oliver.wolff@digia.com>