Code refactoring (#2785)

* chore: pretty theme menu in sidebar

* refactor: renaming component templates

* refactor: create custom `a-statistic` component

* fix: display button text only on large screens

* chore: remove loading background in overview page

* fix: show `Version` text when xray version is unknown

web/html/login.html

@@ -473,8 +473,8 @@
     </transition>
   </a-layout>
 {{template "js" .}}
-{{template "component/themeSwitcher" .}}
-{{template "component/password" .}}
+{{template "component/aThemeSwitch" .}}
+{{template "component/aPasswordInput" .}}
 <script>
   class User {
     constructor() {