[1/2] base: volume panel styles and tweaks

From CM - Support different styles of the volume dialog
allows expanding the dialog to show all adjustable volumes

New setting MODE_VOLUME_OVERLAY defines the style
0 = unchanged - single slider
1 = expandable - button beside to slider to expand - this is the default
2 = expanded - open already expanded

This also adds using setting VOLUME_LINK_NOTIFICATION
to allow adjusting the separation of notification and ringer volumes
default=1

This also already adds the new setting
VOLUME_ADJUST_SOUNDS_ENABLED default=1
to allow disabling the volume adjust sound

PS2:
the usual whitespace cleanup :)

PS3:
change commit message

PS4:
added missing change for VOLUME_LINK_NOTIFICATION in AudioService

PS5:
nitpicks are good :)

Change-Id: I7d8924a4d067a4e587f8c4137c2edd942ca5f435