audio policy: move volume table to XML file

This patch allows to store in XML file volume tables.
The compatibility is maintained for legacy conf file.
Configurable Engine is only compatible with new XML conf.
This patch removes from configurable engine Structure / Settings the volume
table but keep the configurabllity of switching volume profiles from
one another according to criteria like phone state...
(ex: DTMF stream type is following Voice Profile in call)

Change-Id: I78c91bc3378b6c47202abe7b5c1c1e011ff62eed
Signed-off-by: François Gaffie <francois.gaffie@intel.com>