Fix variable name in token validation and add login template

public/templates/login/login.html

@@ -0,0 +1,52 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+    <meta charset="UTF-8">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
+    <title>%appname% // Login</title>
+    <link href="https://fonts.googleapis.com/css2?family=Roboto:wght@400;500;700&display=swap" rel="stylesheet">
+    <script type="importmap">
+        {
+            "imports": {
+                "@material/web/": "https://esm.run/@material/web/"
+            }
+        }
+    </script>
+    <script type="module">
+        import '@material/web/all.js';
+        import {styles as typescaleStyles} from '@material/web/typography/md-typescale-styles.js';
+
+        document.adoptedStyleSheets.push(typescaleStyles.styleSheet);
+    </script>
+    <style>
+        .page-content {
+            display: flex;
+            justify-content: center;
+            text-align: center;
+            align-items: center;
+        }
+
+        .center {
+            display: block;
+        }
+    </style>
+</head>
+<body>
+    <div class="page-content">
+        <div class="center">
+            <h1 class="md-typescale-display-large">%appname%</h1>
+            <h3 class="md-typescale-display-medium">Admin Panel Login</h3><br><br>
+            <md-filled-text-field type="text" id="login_username" placeholder="Username"></md-filled-text-field><br><br>
+            <md-filled-text-field type="password" id="login_password" placeholder="Password"></md-filled-text-field><br><br>
+            <md-filled-button id="login_button">Login</md-filled-button>
+        </div>
+    </div>
+    <script>
+        document.getElementById("login_button").addEventListener("click", function() {
+            var username = document.getElementById("login_username").value;
+            var password = document.getElementById("login_password").value;
+
+        });
+    </script>
+</body>
+</html>