Core: Volume options panel 1/2

P2: Rebased
P4: Rewrite
P5: Rebased
P6: Rewrite to use ContentObserver with handler being VolumePanel
    Also disable link until its fixed
PS7: Re-enable link, remove observer and have VolumePanel handle settings queries
PS8: Register/Unregister observer in correct location for the settings change to take effect immediately

Signed-off-by: Stevespear426 <stephen.k.spear@gmail.com>
Signed-off-by: Rohan Mathur <rohanmathur34@gmail.com>
Signed-off-by: Brandon McAnsh <brandon.mcansh@gmail.com>
Change-Id: I7a5bb88d18b70b9c1bb236afd85270b27cd4106d