Fix issue #28930592: Scoring service binding is not reestablished.

Force stopping the bound scoring service would not automatically
reestablished the binding.

Replaced the custom BroadcastReceiver with a more standard
PackageMonitor implementation that handles the same actions in
addition to force stop.

Also added a few more debug log statements as they were helpful
during my development.

BUG: 28930592
Change-Id: Ic36ea77deb5e2117edc201e97d71be63bdd4230d