Add website login, logout pages and update index with session management

Co-authored-by: iaretechnician <2749183+iaretechnician@users.noreply.github.com>

_website/logout.php

@@ -0,0 +1,28 @@
+<?php
+// Start the website session
+session_name("gameservers_website");
+session_start();
+
+// Include database connection for logging
+require_once('db.php');
+
+// Log the logout
+if (isset($_SESSION['website_username'])) {
+    logger("Website logout: " . $_SESSION['website_username']);
+}
+
+// Destroy all session data
+$_SESSION = array();
+
+// Destroy the session cookie
+if (isset($_COOKIE[session_name()])) {
+    setcookie(session_name(), '', time() - 42000, '/');
+}
+
+// Destroy the session
+session_destroy();
+
+// Redirect to home page
+header('Location: /');
+exit();
+?>