Introduce WaveformBuilder to VibrationEffect

Create a new parcelable RampSegment and introduce
VibrationEffect.startWaveform() method that returns a
WaveformBuilder that allows creating step/ramp waveforms that
changes amplitude and frequency of the effect.

Implementations of VibrationThread and InputManagerService for now just
ignore the new segments and keep existing behavior.

Bug: 167947076
Test: VibrationEffectTest
Change-Id: Ibac895b63196e779457efc297f1f5497a7814ae9