Move user.css to user data (#3952)

Author: christian-byrne

index.html

@@ -4,8 +4,9 @@
     <meta charset="UTF-8">
     <title>ComfyUI</title>
     <meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=no">
-    <link rel="stylesheet" type="text/css" href="user.css" />
     <link rel="stylesheet" type="text/css" href="materialdesignicons.min.css" />
+    <link rel="stylesheet" type="text/css" href="user.css" />
+    <link rel="stylesheet" type="text/css" href="api/userdata/user.css" />
 
     <!-- Fullscreen mode on iOS -->
     <meta name="apple-mobile-web-app-capable" content="yes">