feat: add danmuku plugin documentation and i18n setup guide

- Created a new documentation file for the danmuku plugin with code examples.
- Added comprehensive language settings documentation, including default languages, import instructions, and examples for adding and modifying languages.
- Updated the i18n documentation to reflect changes in language handling and provide clear examples for users.

docs/assets/example/libass.js

@@ -1,44 +0,0 @@
-// npm i artplayer-plugin-libass
-// import artplayerPluginLibass from 'artplayer-plugin-libass';
-
-const art = new Artplayer({
-  container: '.artplayer-app',
-  url: '/assets/sample/video.mp4',
-  fullscreenWeb: true,
-  subtitle: {
-    url: '/assets/sample/style-test.ass',
-  },
-  plugins: [
-    artplayerPluginLibass({
-      // debug: true,
-      workerUrl: 'https://unpkg.com/libass-wasm@4.1.0/dist/js/subtitles-octopus-worker.js',
-      // wasmUrl: 'https://unpkg.com/libass-wasm@4.1.0/dist/js/subtitles-octopus-worker.wasm',
-      fallbackFont: '/assets/misc/SourceHanSansCN-Bold.woff2',
-    }),
-  ],
-})
-
-// init
-art.on('artplayerPluginLibass:init', (adapter) => {
-  console.info('artplayerPluginLibass:init', adapter)
-})
-
-// subtitle switch
-art.on('artplayerPluginLibass:switch', (url) => {
-  console.info('artplayerPluginLibass:switch', url)
-})
-
-// subtitle visible
-art.on('artplayerPluginLibass:visible', (visible) => {
-  console.info('artplayerPluginLibass:visible', visible)
-})
-
-// subtitle timeOffset
-art.on('artplayerPluginLibass:timeOffset', (timeOffset) => {
-  console.info('artplayerPluginLibass:timeOffset', timeOffset)
-})
-
-// destroy
-art.on('artplayerPluginLibass:destroy', () => {
-  console.info('artplayerPluginLibass:destroy')
-})