put the mysql user/pass into MM config

put the mysql user/pass into MM config
now we instanciate the mysql connection only one time, and we keep using it

list_names is now perms-safe
so do members, and (un)subscribe

subscription should have drawbacks atm for lists with a non free subscription policy

one thought : there is no way to distinguish admin mailing lists in mailman. I guess the simplest way is that the owner of those lists has to be root@poly.org or some config thing

added todolist