Add opt-out-of-FLoC headers by default

roles/matrix-nginx-proxy/templates/nginx/conf.d/matrix-base-domain.conf.j2

@@ -5,6 +5,11 @@
 
 	gzip on;
 	gzip_types text/plain application/json;
+
+	{% if matrix_nginx_proxy_floc_optout_enabled %}
+		add_header Permissions-Policy interest-cohort=() always;
+	{% endif %}
+
 	{% for configuration_block in matrix_nginx_proxy_proxy_domain_additional_server_configuration_blocks %}
 		{{- configuration_block }}
 	{% endfor %}