Move PackageMonitorImpl to separate class for re-usability in locales
dir.

Bug: 220076498

Test: atest CtsLocaleManagerTestCases
Test: atest CtsBackupTestCases:AppLocalesBackupTest
Test: atest FrameworksServicesTests:LocaleManagerServiceTest
Test: atest FrameworksServicesTests:LocaleManagerBackupRestoreTest

Change-Id: I54c59bd0a91598c8488979d824d94bfa3c5691e6
6 files changed