[Dovecot] make archive emails undeletable?

[Rob Nichols]

I've been using dovecot for a year or two now, and really like it.  I have a
fairly simple setup, but I think it's time to get a little more advanced.  I
keep an "archive" of all my email, both sent and received.  Every once in a
while I get confused, and accidentally delete something from my archive.  I
also worry that I'll misconfigure a mail client some day and accidentally
wipe out my "trash" folder.  I would like some way to prevent deletion in
several mailboxes.  Is that possible?  It looks like ACL could do this, but
I can't quite figure out where to start.  Any pointers would be greatly
appreciated.

Thanks,
Rob