🔒 Improve NGINX response headers (#700)

Author: frenck

adguard/rootfs/etc/nginx/includes/proxy_params.conf

@@ -11,5 +11,4 @@ proxy_set_header Host $http_host;
 proxy_set_header Upgrade $http_upgrade;
 proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
 proxy_set_header X-Forwarded-Proto $scheme;
-proxy_set_header X-NginX-Proxy true;
 proxy_set_header X-Real-IP $remote_addr;

adguard/rootfs/etc/nginx/includes/server_params.conf

@@ -1,6 +1,5 @@
 root            /dev/null;
 server_name     $hostname;
 
-add_header X-Content-Type-Options nosniff;
-add_header X-XSS-Protection "1; mode=block";
-add_header X-Robots-Tag none;
+add_header X-Content-Type-Options nosniff always;
+add_header X-Robots-Tag none always;