Break up WebRtcVoiceServiceModule into the module and a separate class implementing IWebRtcVoiceService

[Misterblue]

WebRtcVoiceServiceModule.cs does two things. The ISharedRegionModule should not also implement IWebRtcVoiceServer.

Break up this class into two classes to make the functional distinction clear and to remove the various dependencies since the region module also implements the service interface.