🔧(front) configure x-frame-options to DENY in nginx conf (#1084)

The API has the response header x-frame-options configure to DENY and
nothing is configure in the nginx configuring managing the frontend
application. We want to have the same value. The header is added on all
locations.

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

@@ -7,10 +7,14 @@ server {
 
   location / {
       try_files $uri index.html $uri/ =404;
+
+      add_header X-Frame-Options DENY always;
   }
 
   location ~ "^/docs/[0-9a-f]{8}-[0-9a-f]{4}-4[0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}/?$" {
       try_files $uri /docs/[id]/index.html;
+
+      add_header X-Frame-Options DENY always;
   }
 
   error_page 404 /404.html;