Give consistent names to properties controlling camera shutter sound

There is a property named "ro.camera.sound.force" which control if camera sound should be played
even if phone is in silent mode. This is standard property and it is not affected by this change.

Another property (used for HTC vivo/vivow/mecha devices) disables camera shutter sound on system level.
Currently it is named "persist.camera.shutter.disable". Renamed to "ro.camera.sound.disabled" to
keep consistent naming with previous option. Also, this property is intended to be read only
and therefore should live in "ro.*" namespace.

Adding support for third property, "persist.sys.camera-mute" which will allow control over camera
shutter sound if it is not disabled by prevoius property.

imported from gingerbread f62a0e8b

Change-Id: I447f9bc61ca20022d5b62ef9ea231d6a1d0b38d7