audio policy: introduction of AudioProfile

In order to be able to declare the possible sample
specifications for an Audio Port (a given format, a list of
sample rates, a list of channels), a new object AudioProfile is
introduced.

Change-Id: Ie3ca3400f05984e7b4132fc7ba90020eb4d998c7
Signed-off-by: François Gaffie <francois.gaffie@intel.com>