feat: add i18n support documentation and language import examples

- Created a new documentation file for language settings in i18n.
- Added examples for setting default languages and importing additional languages.
- Included instructions for adding and modifying languages in the ArtPlayer plugin.
- Introduced a new plugin: artplayer-plugin-liquid-glass with various build formats (legacy, mjs, etc.).

docs/assets/js/common.js

@@ -63,6 +63,7 @@
       './assets/ts/artplayer-plugin-vast.d.ts',
       './assets/ts/artplayer-plugin-vtt-thumbnail.d.ts',
       './assets/ts/artplayer-plugin-document-pip.d.ts',
+      './assets/ts/artplayer-plugin-liquid-glass.d.ts',
       './assets/ts/artplayer-proxy-canvas.d.ts',
       './assets/ts/artplayer-proxy-mediabunny.d.ts',
       './assets/ts/artplayer.d.ts',