feat: add artplayer-plugin-audio-track for audio synchronization with video

- Implemented the audio track plugin for ArtPlayer, allowing audio to be synchronized with video playback.
- Added main functionality in `src/index.js` to handle audio playback, synchronization, and event listeners for play, pause, seek, and volume changes.
- Created TypeScript definitions for the plugin in `types/artplayer-plugin-audio-track.d.ts`.
- Included necessary build files in `dist/` for various module formats (CommonJS, ES Module, and legacy).
- Updated package metadata in `package.json` and added a README for documentation.
- Added `.npmignore` to exclude unnecessary files from the package.

docs/assets/example/audio.track.js

@@ -0,0 +1,14 @@
+// npm i artplayer-plugin-audio-track
+// import artplayerPluginAudioTrack from 'artplayer-plugin-audio-track';
+
+var art = new Artplayer({
+    container: '.artplayer-app',
+    url: '/assets/sample/sprite-fight.mp4',
+    plugins: [
+        artplayerPluginAudioTrack({
+            url: '/assets/sample/sprite-fight.aac',
+            offset: 0, 
+            sync: 0.3, 
+        }),
+    ],
+});