Add Mailman include option file so options aren't lost on update

Hello,

I'm been writing up about how to use Mailman to send newsletters.

I cam accross a limition with the default cPanel configuration, in order to add a one-click unsubscribe link you have to add

OWNERS_CAN_ENABLE_PERSONALIZATION = 1

http://wiki.list.org/pages/viewpage.action?pageId=4030545

This option allows messages to have a personalized content per recipient. Apart from maybe more ressource usage I don't see why this wouldn't be enabled.

Once enabled you can add a single click unsubscribe link to your newsletters which makes much more sense.

All we need is a file in which to put custom variables that are added to /usr/local/cpanel/3rdparty/mailman/Mailman/mm_cfg.py when mailman is updated.