[Sb] New unified battery icon

This CL adds a new style of battery drawable, `BatteryLayersDrawable`,
which renders a battery meter via manual compositon and arrangement of
layers. The procss is similar to the existing ThemedBatteryDrawable,
where we use custom renering to achieve the correct UI encapsulated in a
drawable.

This new drawable employs the use of a view data class, `BatteryMeterState`, that can fully
describe the desired view state, and encapsulaes battery theme colors in
a `BatteryColors` class, of which there are light and dark variants.

Test: compile
Bug: 314812750
Flag: NONE
Change-Id: I62485c1797d0da680478e6d726f6d90df357ab1e