Create package-level last time usage stats for app hibernation

Create a user-agnostic package-level last time used usage stats for app
hibernation. Usage is updated when USER_INTERACTION or
APP_COMPONENT_USED event reported. Also moved checkAndGetTimeLocked and
convertToSystemTimeLocked methods up to UsageStatsService class and
refactored usages.

Bug: 183142974
Test: atest CtsUsageStatsTestCases:UsageStatsTest
Test: atest UsageStatsServiceTest
Test: atest UserUsageStatsServiceTest

Change-Id: I93d8653bb92b98af8f6b57156eb1139fbd7e562a