feat: add ThermionFlutterOptions classes, rename interface parameter for offsetTop and ensure pixelRatio is passed to resizeTexture

thermion_flutter/thermion_flutter_web/lib/thermion_flutter_web_options.dart

@@ -0,0 +1,8 @@
+import 'package:thermion_flutter_platform_interface/thermion_flutter_platform_interface.dart';
+
+class ThermionFlutterWebOptions extends ThermionFlutterOptions {
+  bool createCanvas;
+  bool importCanvasAsWidget;
+ 
+  ThermionFlutterWebOptions({this.importCanvasAsWidget = false, this.createCanvas = true, String? uberarchivePath}) : super(uberarchivePath:uberarchivePath);
+}