move flutter_filament plugin to federated structure

flutter_filament_federated/flutter_filament/macos/Classes/FlutterFilamentTexture.swift

@@ -0,0 +1,30 @@
+import Foundation
+import GLKit
+import FlutterMacOS
+
+public class FlutterFilamentTexture : DartFilamentTexture,  FlutterTexture {
+    
+    var flutterTextureId: Int64 = -1
+    var registry: FlutterTextureRegistry
+    
+    init(registry:FlutterTextureRegistry, width:Int64, height:Int64) {
+        self.registry = registry
+        super.init(width:width, height:height)    
+        self.flutterTextureId = registry.register(self)
+            
+    }
+    
+    public func copyPixelBuffer() -> Unmanaged<CVPixelBuffer>? {
+        return Unmanaged.passRetained(pixelBuffer!);
+    }
+    
+    public func onTextureUnregistered(_ texture:FlutterTexture) {
+        print("Texture unregistered")
+    }
+    
+    public func destroy() {
+        self.registry.unregisterTexture(self.flutterTextureId)
+        self.destroyTexture()
+    }
+    
+}