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。
```

i18n/en.properties

@@ -0,0 +1,54 @@
+common.previousPage=Previous
+common.nextPage=Next
+common.more=More
+common.all=All
+common.noPosts=No Posts
+common.comment=Comment
+common.edit=Edit
+common.publishedOn=Published on {0}
+common.visitCount={0} Visits
+
+widget.categories.title=Categories
+widget.popularPosts.title=Popular Posts
+widget.tags.title=Tags
+widget.latestComments.title=Latest Comments
+widget.profile.postCount.label=Posts
+widget.profile.categoryCount.label=Categories
+widget.profile.commentCount.label=Comments
+widget.profile.visitCount.label=Visits
+
+page.archives.title=Archives
+page.archives.date={0} / {1}
+page.links.title=Links
+page.moments.title=Moments
+page.photos.title=Photos
+page.tags.title=Tags
+page.tags.morePosts=More Posts
+page.tag.title=Tag: {0}
+page.category.title=Category: {0}
+page.author.title=Author: {0}
+page.error.backToHome=Back to Home
+page.post.toc=Table of Contents
+
+fragment.header.search=Search
+fragment.header.menu=Menu
+fragment.header.console=Console
+fragment.header.logout=Logout
+fragment.header.login=Login
+fragment.layout.toTop=Back to Top
+fragment.tagFilter.allTags=All Tags
+fragment.shareModal.title=Share
+fragment.shareModal.copy=Copy
+fragment.shareModal.copied=Copied
+fragment.postCard.pinned=Pinned
+
+jsModule.colorSchemeSwitcher.dark=Dark
+jsModule.colorSchemeSwitcher.light=Light
+jsModule.colorSchemeSwitcher.auto=Auto
+jsModule.share.qzone=QQ Zone
+jsModule.share.weibo=Weibo
+jsModule.share.douban=Douban
+jsModule.share.wechat=WeChat
+jsModule.share.native=System
+jsModule.share.windowTitle=Share
+jsModule.upvote.networkError=Network request failed, please try again later