🐛(nginx) fix / location to handle new static pages

The / location is not trying the $uri/index.html file. We should try
this instad of $uri/ because when a new static page is added, we always
have this pattern.

src/frontend/apps/impress/conf/default.conf

@@ -6,7 +6,7 @@ server {
   root /usr/share/nginx/html;
 
   location / {
-      try_files $uri index.html $uri/ =404;
+      try_files $uri index.html $uri/index.html =404;
 
       add_header X-Frame-Options DENY always;
   }