Audio effects: define interface between EffectModule and audio framework

This is in preparation of the addition of audio effects attached to a
specific audio device that will not be attached to a particular
ThreadBase or Effectchain.

Create an clean callback interface used by the EffectModule to interact
with the rest of the audio framework. This callback must be implemented
by the EffectModule parent (e.g an EfffectChain).

Als refactor EffectHandle enabled(), disable() and disconnect methods()
to avoid dealing with the ThreadBase directly.

Bug: 136294538
Test: make
Change-Id: I9160f88f7fbb0447b5e679260bf0401d3af591d2