Task 9: Add CSRF tokens to form templates and backend processors

Updated forms with hidden CSRF token fields:
- comment_box.php - Comment form
- course_details.php - Course booking form
- campsites.php - Campsite addition modal form
- bar_tabs.php - Bar tab creation modal form
- membership_application.php - Membership application form

Updated backend processors with CSRF validation:
- create_bar_tab.php - Bar tab AJAX processor
- add_campsite.php - Campsite form processor
- submit_order.php - Order submission processor

All forms now require validated CSRF tokens before processing, preventing cross-site request forgery attacks.

membership_application.php

@@ -55,6 +55,7 @@ if (!empty($bannerImages)) {
             <div class="col-lg-12">
                 <div class="comment-form bgc-lighter z-1 rel mb-30 rmb-55">
                     <form id="registerForm" name="registerForm" action="process_application.php" method="post" data-aos="fade-left" data-aos-duration="1500" data-aos-offset="50">
+                        <input type="hidden" name="csrf_token" value="<?php echo generateCSRFToken(); ?>">
                         <div class="section-title">
                             <div id="responseMessage"></div> <!-- Message display area -->
                         </div>