Element More security headers

More Production ready nginx headers for Matrix client element.

roles/matrix-nginx-proxy/templates/nginx/conf.d/matrix-client-element.conf.j2

@@ -3,9 +3,12 @@
 {% macro render_vhost_directives() %}
 	gzip on;
 	gzip_types text/plain application/json application/javascript text/css image/x-icon font/ttf image/gif;
-	add_header Strict-Transport-Security "max-age=31536000; includeSubDomains" always;
+	add_header Strict-Transport-Security "max-age=31536000; includeSubDomains; preload" always;
 	add_header X-Content-Type-Options nosniff;
+	add_header X-XSS-Protection "1; mode=block";
 	add_header X-Frame-Options SAMEORIGIN;
+	add_header Content-Security-Policy "frame-ancestors 'none'; require-trusted-types-for 'script'; base-uri 'self'";
+	add_header Referrer-Policy "strict-origin-when-cross-origin";
 	{% for configuration_block in matrix_nginx_proxy_proxy_element_additional_server_configuration_blocks %}
 		{{- configuration_block }}
 	{% endfor %}