Add config for the auto restricted bucket on abusive bg battery drain

By default it's OFF. It could be turned ON in the devices with
high confidence on the battery measurements - meaning that, on thoese
devices, the apps would be moved to restricted standby bucket level
if system detects they're draining significant amount of battery
in the background.

Bug: 203105544
Test: atest FrameworksMockingServicesTests:BackgroundRestrictionTest
Test: dumpsys activity -a
Change-Id: I74cc1f7e463e5dbed912b71969298ab3f97f1618