Add email templates for user notifications and account management

- Created a base email template (base.html) for consistent styling across all emails.
- Added moderation approval email template (moderation_approved.html) to notify users of approved submissions.
- Added moderation rejection email template (moderation_rejected.html) to inform users of required changes for their submissions.
- Created password reset email template (password_reset.html) for users requesting to reset their passwords.
- Developed a welcome email template (welcome.html) to greet new users and provide account details and tips for using ThrillWiki.

django/staticfiles/admin/js/popup_response.js

@@ -0,0 +1,16 @@
+/*global opener */
+'use strict';
+{
+    const initData = JSON.parse(document.getElementById('django-admin-popup-response-constants').dataset.popupResponse);
+    switch(initData.action) {
+    case 'change':
+        opener.dismissChangeRelatedObjectPopup(window, initData.value, initData.obj, initData.new_value);
+        break;
+    case 'delete':
+        opener.dismissDeleteRelatedObjectPopup(window, initData.value);
+        break;
+    default:
+        opener.dismissAddRelatedObjectPopup(window, initData.value, initData.obj);
+        break;
+    }
+}