initial work to split into dart_filament and flutter_filament

flutter_filament/example/macos/Flutter/GeneratedPluginRegistrant.swift

@@ -0,0 +1,14 @@
+//
+//  Generated file. Do not edit.
+//
+
+import FlutterMacOS
+import Foundation
+
+import flutter_filament
+import path_provider_foundation
+
+func RegisterGeneratedPlugins(registry: FlutterPluginRegistry) {
+  SwiftFlutterFilamentPlugin.register(with: registry.registrar(forPlugin: "SwiftFlutterFilamentPlugin"))
+  PathProviderPlugin.register(with: registry.registrar(forPlugin: "PathProviderPlugin"))
+}