refactor(js): avoid use of window.XXX and move to import/export

- change worker: do not cache html pages (not necessary)
- remove use of window.XXX and maximize import/export,
  this will provide more clarety,
  show circular dependencies + you will benefit IDE help

static/admin.html

@@ -5,10 +5,6 @@
         <meta name="viewport" content="width=device-width, initial-scale=1.0" />
         <title>OxiCloud — Admin Panel</title>
         <script src="/js/core/theme-init.js"></script>
-        <script src="/js/core/i18n.js" defer></script>
-        <script src="/js/core/icons.js" defer></script>
-        <script src="/js/core/formatters.js" defer></script>
-        <script src="/js/core/csrf.js" defer></script>
         <link rel="stylesheet" href="/css/main.css" />
         <link rel="stylesheet" href="/css/views/admin.css" />
     </head>
@@ -608,6 +604,6 @@
             </div>
         </div>
 
-        <script src="/js/views/admin/admin.js" defer></script>
+        <script type="module" src="/js/views/admin/admin.js"></script>
     </body>
 </html>