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-document-pip.d.ts

@@ -18,5 +18,5 @@ declare const artplayerPluginDocumentPip: (option: Option) => (art: Artplayer) =
 
 export default artplayerPluginDocumentPip
 
-export = artplayerPluginDocumentPip
-export as namespace artplayerPluginDocumentPip;
+export = artplayerPluginDocumentPip;
+export as namespace artplayerPluginDocumentPip;