[battery] Compose-based battery icon

This CL adds the data/domain/ui level classes to support a
fully-composified battery icon, and also adds that icon

The icon itself is built in UnifiedBattery, and contains a few
conveniences that we will likely end up using in the future, such as a
pure, viewmodel-less version of the battery icon that is suitable for
the battery chip, a well as a view binder for use in an AndroidView.

Test: BatteryRepositoryTest
Test: BatteryInteractorTest
Test: BatteryViewModelTest
Test: manual
Bug: 314812750
Bug: 391605373
Flag: EXEMPT unused code as of yet

Change-Id: I894661c1374e1ba2cc91eb3f4b0673ddb191660a