Implement BatteryUsageStatsStore

Bug: 187223764
Test: atest FrameworksCoreTests:BatteryUsageStatsStoreTest

Change-Id: I66bbb173f402e795c900ccf3bc82b8fb210142a4
Merged-In: I66bbb173f402e795c900ccf3bc82b8fb210142a4
(cherry picked from commit 2a0460f70111601ba9088442b63e833c06766d7b)
5 files changed