[Grml] mailinglist setup modification

Hello grml-users,

due to the fact that the grml-user-mailinglist is open for all users (you don't need to be subscribed to the mailinglist to write emails to the list) spam arrives the list too. :-((

I plan to restrict sending mails to the mailinglist to members only. If you don't think that's a good idea please let me know, otherwise I'll activate the restriction in the next few days.

regards, -mika-