Use a separated flag for archiving feature in Settings

The new flag will replace the current PM-flag eventually, once they reach the same rollout status. Until then both flags are kept concurrently, to avoid a rollback of the feature.

This is done to reduce risk and potentially enable an isolated rollback
of Settings related logic, while keeping system logic intact.

Additionally, fix bug by replacing `System.getProperty("pm.archiving.enabled")` to `SystemProperties.getBoolean("pm.archiving.enabled", false)`

Test: InstalledAppCounterTest, AppButtonsTest, HibernationSwitchPreferenceTest
Bug: 323164382
Change-Id: I44a41d6a43a12134c4e3aa5df8ad6a9eb91758d4