Add Mass Storage Mode device

- Increment version number to 3.2.0~rc1
- Move all Mass Storage Mode related functionality from System device to a new device

Open-webOS-DCO-1.0-Signed-off-by: Pekka Ropo <pekka.ropo@palm.com>

Change-Id: I29e0fb843650cf60999b698829334c44cd053904