mixer must play in 4a and not in pulse

The more we use 4a and the more we plug apps out of pulse.

The Mixer should show the control listed in 4a not the one from pulse.

The list of which control should be displayed shoudl be extracted from a 4a HAL and not be too long.

Currently we have too many control to give any meaning.

Some should not be user tunable (e.g. emergency and warning)