feat: Implement OFX plugin support infrastructure

This commit adds comprehensive support for OFX plugins in Olive, including:

- Add plugin node infrastructure with getPlugin() method
- Implement OliveHost for managing OFX plugin instances
- Create OliveInstance to handle plugin parameter and timeline interactions
- Add OliveClip implementation for plugin clip handling
- Implement region of definition (RoD) and region of interest (RoI) functionality
- Add interactive mode support in Current class
- Integrate plugin rendering into RenderProcessor
- Fix include dependencies and remove unused OlivePlugin.cpp reference

app/pluginSupport/OliveInstance.cpp

@@ -147,6 +147,12 @@ void OliveInstance::getRenderScaleRecursive(double &x, double &y) const
 	x = 1.0;
 	y = 1.0;
 }
+OFX::Host::Param::Instance *
+OliveInstance::newParam(const std::string &name,
+						OFX::Host::Param::Descriptor &Descriptor)
+{
+
+}
 
 OFX::Host::ImageEffect::ClipInstance *OliveInstance::newClipInstance(
 	OFX::Host::ImageEffect::Instance *plugin,