Introduce global package hibernation

Introduce the concept of global package hibernation / package-level
hibernation. This opens the way for optimizations at the package or
APK level based off usage across all users.

Bug: 175829330
Test: atest AppHibernationServiceTest
Test: adb shell cmd app_hibernation get-state --global
com.google.android.deskclock

Change-Id: Ic989fc09a4c60f3bbf28b34fe38fa07e77eedacb