Allow applications to define failure handlers

Fixes: 37956764
Test: Manual
Test: Create a test app with no handler, see it's not passed to the installer
Test: Create a test app with a handler, see it's passed to the installer
Test: Create a test app with multiple handlers, see one is passed to the installer
Test: Create a test app with a handler defined in a split, see it's not passed to the installer
Change-Id: Idfc3648154afca7ec300019d9695417274118d6f