Introduce device config for vibration scales

Add two new keys to core/res/config.xml to allow device configurable
scale factors to be used for each vibration intensity setting value.

The configurations must provide a scale value to be used directly for
each user intensity setting value: LOW, MEDIUM and HIGH.

The framework logic around device default setting vs user setting will
be ignored on devices that provide this direct scale value config, so
the user setting will translate directly into a scale factor to be used
as a direct multiplier for the input values.

There is also a separate config key for external vibrations (a.k.a
audio-coupled haptics), which can be used to configure their scaling
separately. If no config is provided, the vibration config will still be
applied to external vibrations for consistency with vibration effects.

Fix: 427503922
Flag: android.os.vibrator.vibration_scale_device_config_enabled
Test: FrameworksVibratorServicesTests
Change-Id: Ic5d67f6a45865d054f96bb04e692578624a69a44