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/ts/artplayer-plugin-chapter.d.ts

@@ -17,5 +17,5 @@ declare const artplayerPluginChapter: (option: Option) => (art: Artplayer) => Re
 
 export default artplayerPluginChapter
 
-export = artplayerPluginChapter
-export as namespace artplayerPluginChapter;
+export = artplayerPluginChapter;
+export as namespace artplayerPluginChapter;