Added velocity scalar and updated spring values

Updated spring values to the latest ones agreed in design. In addition,
added a velocity multiplier that only affects after it absorbs an impact
at the scroll boundary. This will help to increase the spring behavior
when we fling the content, but keeping it controlled when we pull and
release.

Bug: 183768138
Test: ran EdgeEffectTest and visual
Change-Id: I4ed7b01dd42a9a5adda637917369c349a6ae2f76