feat: add i18n supports (#214)

添加界面的 i18n 支持。

/kind feature

Fixes https://github.com/halo-dev/theme-earth/issues/198
Fixes https://github.com/halo-dev/theme-earth/issues/75

```release-note
添加界面的 i18n 支持。
```

templates/modules/widgets/popular-posts.html

@@ -3,7 +3,7 @@
 >
   <h2 class="inline-flex items-center gap-2 text-base dark:text-slate-50">
     <span class="i-tabler-stairs-up text-lg text-red-600 dark:text-red-700"></span>
-    热门文章
+    <th:block th:text="#{widget.popularPosts.title}"></th:block>
   </h2>
   <div>
     <ul
@@ -19,7 +19,7 @@
             </h3>
             <p
               class="text-xs tabular-nums text-gray-500 dark:text-slate-400"
-              th:text="${#dates.format(post.spec.publishTime,'yyyy-MM-dd')+' 发布'}"
+              th:text="${#dates.format(post.spec.publishTime,'yyyy-MM-dd')}"
             ></p>
           </div>
           <div class="inline-flex items-center gap-1 text-xs text-gray-600 dark:text-slate-500">