audiopolicy: apm: factorize internal patch creation/release

This CL removes duplicated code for patch creation for
-voice call
-system API to create patches.
-system API to start/stop AudioSource

It creates internal methods to create/release Audio Patches.

The benefit of this rework is to have startAudioSource now working
whatever Sw or HW bridging is used.

Test: Voice Call
Bug: 136294538
Change-Id: I82738d116abd94f7738fce8ca3a1c3466942060a
Signed-off-by: François Gaffie <francois.gaffie@renault.com>