[incremental/pm] LauncherApps APIs for loading state and progress

Exposing package state changes and progress changes via LauncherApps
and LauncherActivityInfo as public APIs.

BUG: 165841645
Test: builds (will add CTS tests)
CTS-Coverage-Bug: 168925573
Change-Id: I2b5ea698799f9a762b7d9c79d62636d3db187c1f