Flatten RangedAudioParameter into AudioProcessorParameter

The parameters RangedAudioParameter is inheriting are barely used. On the other hand, the AudioProcessorParameter lacks crucial functionality, like the ParameterID and the range conversion, that are needed almost always.
This means in practice, that the user has to add dynamic_casts or keeps references to paraameters just to avoid casting.

Moving all functionality of RangedAudioParameter into the base class would improve the user experience a lot. Please consider this change.