Remove libbatteryservice.

libbatteryservice and IBatteryPropertiesRegistrar.java used to
define the binder connection between framework/storaged and healthd.
Now that framework/storaged and healthd are communicated via hwbinder
(android.hardware.health@2.0 HAL), this library can be removed.

Test: pass
Bug: 68724651
Change-Id: I6e5709e932c4ad6e3bddf21912af244303894447