please create a thunderbird schleuder plugin

a thunderbird plugin that is designed specifically for interacting with schleuder would be a pretty sweet thing. it would:

• somehow detect that a message is going to a schleuder list
• present a pleasant gui for doing the things that you might reasonably do
• modify the message during send to include the selected activities

I have some ideas about how each of these things would be done; hopefully they'd make the lives of people like @sajolida easier and let them be more relaxed tigers with fur that is less singed (see the comment on #373 (closed))