audio: Allow Module subclasses to customize Configuration

When a vendor HAL reuses libaudioserviceexampleimpl,
a subclass of Module cannot change Configuration.

This change adds virtual method Module::initializeConfig(),
then a vendor HAL can override it to load custom Configuration.

Test: atest VtsHalAudioCoreTargetTest
Change-Id: I63fa8d70f3c4e13c8938070ee5431ebefd36bb58