use RWTH VR Toolkit IsMaster and cluster event wrapper

Source/VAPlugin/Private/Renderer/VABaseRenderer.cpp

...APlugin/Private/SignalSources/VAAudiofileSignalSource.cpp

...APlugin/Private/SoundSource/VAAbstractSourceComponent.cpp

Source/VAPlugin/Private/VAPlugin.cpp

Source/VAPlugin/Private/VAPlugin.h

Source/VAPlugin/Private/VAReceiverActor.cpp

Source/VAPlugin/Private/VAUtils.cpp

Source/VAPlugin/Public/VAReceiverActor.h

Source/VAPlugin/VAPlugin.Build.cs