Add rewrites for json api

src/freedombone-utils-web

       echo '';
       echo '  access_log /dev/null;';
       echo '  error_log /dev/null;';
+      echo '';
+      echo '  location /icons {';
+      echo '    autoindex on;';
+      echo '    break;';
+      echo '  }';
+      echo '';
+      echo '  rewrite ^/plinth/(.*)$ /api.json last;';
+      echo '';
+      echo '  location / {';
+      echo "    root /var/www/${local_hostname}/htdocs/plinth;";
+      echo '    index api.json /api.json;';
+      echo "    error_page 405 = \$uri;";
+      echo '  }';
       echo '}';
       echo '';
       echo 'server {';
     nginx_security_options "${local_hostname}"
 
     { echo '  add_header Strict-Transport-Security max-age=0;';
+      echo '';
+      echo '  location /icons {';
+      echo '    autoindex on;';
+      echo '    break;';
+      echo '  }';
+      echo '';
+      echo '  rewrite ^/plinth/(.*)$ /api.json last;';
+      echo '';
+      echo '  location / {';
+      echo "    root /var/www/${local_hostname}/htdocs/plinth;";
+      echo '    index api.json /api.json;';
+      echo "    error_page 405 = \$uri;";
+      echo '  }';
       echo '}'; } >> "$nginx_file"
 
     if [ ! -f "/etc/ssl/certs/${local_hostname}.crt" ]; then