breaking changes: algolia 升級至 v4

feat:  本地搜索增加數據庫加載中和搜索中 loading 顯示
feat: 更改文章美化後,列表的顯示效果 closed #693 closed #686
improvement: UI 微調

layout/includes/page/categories.pug

@@ -1,5 +1 @@
-.category-lists
-  .category-title.is-center= _p('page.category')
-    |  - 
-    span.category-amount= site.categories.length
-  div!= list_categories()
+.category-lists!= list_categories()

layout/includes/page/default-page.pug

@@ -1,4 +1,2 @@
 #article-container
-  if top_img === false
-    h1.page-title= page.title
   != page.content

layout/includes/page/flink.pug

@@ -1,7 +1,4 @@
 #article-container
-  if top_img === false
-    h1.page-title= page.title
-
   .flink
     if site.data.link
       each i in site.data.link