[Firm] Open up the mailing list

[Matthias Braun]

Hi,

I'd like to open up the firm mailing list to the public. So anyone can
subscribe and unsubscribe. Archives only go back to September 2013:

https://lists.ira.uni-karlsruhe.de/mailman/pipermail/firm/

If there's a real need then I would open up a new closed core developers
mailing list, but I'd really prefer to keep development in the open.

Another question would be what to forward to this list. We could:

* Forward git pushs (aka. commits). IMO the rss feeds work good enough
so I would not do this
* Forward messages about new/changed tickets in the bugtracker. I'd be
in favor of this.

Greetings
	Matthias