Process the incoming uninstall intent to this app

This change will simply accept the incoming intent, extract some data from it like the action and whether uninstall package is valid, callback exists or not etc.

Bug: 182205982
Test: builds successfully
Test: No CTS Tests. Flag to use new app is turned off by default

Change-Id: I6280bef06689735214eb05c2f93753c6f01afe5b