Add battery indicator to bluetooth icon

This cl creates BluetoothDeviceLayerDrawable, which contains two
drwable:
1. previous bluetooth device drawable
2. battery drawable showing the battery level

If connected bt device has battery level, we will use this
LayerDrawable both in bluetooth main page and detail page.

Also, battery drawable is reused from BatteryMeterDrawableBase, we
rotate base drawable by 90 degree and update the spec a little bit.

Bug: 63393322
Test: RunSettingsLibRoboTests

Change-Id: I55313940576523dcbeb65a6e20e41289da8a3e0c
Merged-In: I55313940576523dcbeb65a6e20e41289da8a3e0c