feat: 增加 aside 最新評論部件

style： 部分css調整和html優化
improvements: 刪除pwa中的theme-color配置，默認生成meta theme-color  close #340
improvements: 優化最後更新時間顯示（1小時內顯示 剛剛，1小時到24小時 顯示 xx小時前，1天到365天 顯示 xx天前，365天后直接顯示日期）

_config.yml

@@ -644,6 +644,25 @@ runtimeshow:
   enable: false
   publish_date:
 
+# Aside widget - Newest Comments
+newest_comments:
+  enable: false
+  limit: 6
+  avatar: true
+  leancloud:
+    enable: false
+    appId: # leancloud application app id
+    appKey: # leancloud application app key
+    serverURL: # This configuration is suitable for domestic custom domain name users, overseas version will be automatically detected (no need to manually fill in)
+    default_avatar: mp # mp/identicon/monsterid/wavatar/retro/robohash/blank
+  github_issues:
+    enable: false
+    repo:
+  disqus:
+    enable: false
+    forum:
+    api_key:
+
 # Bottom right button (右下角按鈕)
 # --------------------------------------
 
@@ -763,7 +782,6 @@ lazyload:
 # pwa:
 #   enable: false
 #   manifest: /image/pwa/manifest.json
-#   theme_color: "#fff"
 #   apple_touch_icon: /image/pwa/apple-touch-icon.png
 #   favicon_32_32: /image/pwa/32.png
 #   favicon_16_16: /image/pwa/16.png