Redesign how interface instantiation works

Transferring some argument pack is much easier than trying to
deserialize into an existing object when you also have to transfer more
information than just that object.

src/wine-host/bridges/vst3.cpp

@@ -66,17 +66,13 @@ void Vst3Bridge::run() {
                 //         ID to that.
                 //       - Add that ID to `YaComponent` and set it in the object
                 //         we create here.
-                //       - In case `factory` is a null pointer, allow returning
-                //         `nullopt`. Not sure how that is going to work with
-                //         the deserialization.
-                if (!component) {
-                    // TODO: Handle
+                if (component) {
+                    // TODO: Generate a unique instance ID
+                    return std::make_optional<YaComponent::Arguments>(
+                        component, 420691337);
+                } else {
+                    return std::nullopt;
                 }
-
-                // TODO: Implement `YaComponentHostImpl` and create an instance
-                //       based on `component`
-                YaComponent* removeme = nullptr;
-                return *removeme;
             },
             [&](const WantsPluginFactory&) -> WantsPluginFactory::Response {
                 return *plugin_factory;