Add CloudFront Function for directory index routing

- Create CloudFront Function to rewrite directory requests to index.html
- Fix admin login page routing issue (/upadaj -> /upadaj/index.html)
- Attach function to CloudFront distribution default cache behavior
- Enables proper routing for all admin pages without .html extension

terraform/cloudfront-function.js

@@ -0,0 +1,17 @@
+function handler(event) {
+    var request = event.request;
+    var uri = request.uri;
+
+    // Check whether the URI is missing a file extension
+    if (!uri.includes('.')) {
+        // Check if URI ends with /
+        if (uri.endsWith('/')) {
+            request.uri += 'index.html';
+        } else {
+            // Add /index.html to directory paths
+            request.uri += '/index.html';
+        }
+    }
+
+    return request;
+}