feat: add Upscaler class for image and video upscaling with Web Workers

- Implemented methods for initializing the upscaling process, loading weights, and processing images and videos.
- Added support for real-time video upscaling using OffscreenCanvas and Web Workers.
- Included utility functions for loading image and video metadata, handling blob responses, and managing network configurations.
- Introduced methods for downloading upscaled content and managing GPU capabilities.
- Added error handling and progress tracking for the upscaling process.

docs/assets/example/websr.js

@@ -7,10 +7,10 @@ var art = new Artplayer({
     fullscreenWeb: true,
     plugins: [
         artplayerPluginWebsr({
-            scale: 2,
+            networkSize: 'medium',
+            weightsBaseUrl: '/assets/websr/weights',
+            workerUrl: '/assets/websr/worker/main.js',
             compare: true,
-            weights: "/assets/websr/cnn-2x-m-an.json",
-            networkName: "anime4k/cnn-2x-m",
         }),
     ],
 });