sysutils/graylog: update to 4.1.3 and provide a valid default .conf

Summary:
ChangeLog: https://docs.graylog.org/en/4.1/pages/changelog.html#graylog-4-1-3

Reported by: Daniel Morante <daniel@morante.net>
Submitted by: Charles Gonçalves <charles@freebsdbrasil.com.br>
Sponsored by: FreeBSD Brasil
Sponsored by: SkunkWerks, GmbH
Differential Revision: https://reviews.freebsd.org/D31521