Separate notification/ring volume sliders in UI

Separate the logic between notification slider and ring slider in
setting through new logic in SeekBarVolumizer when ring is not aliased
with notification in config.xml.

Start the notif/ring separation code but hide it in the new SysUI volume dialog.

Bug: b/38477228

Test: manual
      (1) With ring/notif alias set to false, in the Sound Settings, drag ring volume to zero. Verify notification volume snaps to zero as well. Then drag the notification volume out of zero. Verify that notification volume is stable at the new value and does not wrongly snap back to zero.
      (2) With the alias set to false, drag media volume to zero, midpoint, and max. Verify the slider control is stable, and that the audio level corresponds relative to the level on UI.
      (3) Repeat test 2 with the alias set to true.

Change-Id: Ifff4c06a952ba13dc6d6830fea5fe47651fa5b2e