retire (delete) the tor-exec list please

We made the tor-exec list many years ago, as a place for a subset of the board to make strategy plans, approve expenses, etc that didn't need to involve the whole board.

It's been many years now since we used it for that purpose, and in fact the only people left on the list now are Roger, Nick, and Shari, and we don't use it.

I asked Shari and Isa if we should delete it, and they chose yes.

It looks like it has archives. They can be deleted too.

Thanks!