feat: 美化 firefox 瀏覽器滾動條

fix: Utterances 評論區在多個頁面顯示的是同一個評論區
fix: 修復評論配置爲 Livere 和 Facebook Comments 時，最新評論模塊仍然顯示的 bug
improvement: blueimp_md5 CDN 可配置
improvement: timeline 優化
improvement: css優化
improvement: 友情鏈接優化

scripts/events/config.js

@@ -24,6 +24,7 @@ hexo.extend.filter.register('before_generate', () => {
     // comments
     gitalk: 'https://cdn.jsdelivr.net/npm/gitalk@latest/dist/gitalk.min.js',
     gitalk_css: 'https://cdn.jsdelivr.net/npm/gitalk/dist/gitalk.min.css',
+    blueimp_md5: 'https://cdn.jsdelivr.net/npm/blueimp-md5/js/md5.min.js',
     valine: 'https://cdn.jsdelivr.net/npm/valine/dist/Valine.min.js',
     disqusjs: 'https://cdn.jsdelivr.net/npm/disqusjs@1/dist/disqus.js',
     disqusjs_css: 'https://cdn.jsdelivr.net/npm/disqusjs@1/dist/disqusjs.css',