Empty users' To-Do list

As a post-import clean up step, it would be sweet to empty every user's To-Do list (https://gitlab.tails.boum.org/dashboard/todos): my user has more than 3k To-Do's post-migration. While emptying the list is one click away for every user, I'm concerned that starting with an unusable To-Do list will make some of us get used to ignoring it right from the beginning, which would be a problem.

If emptying To-Do lists is as simple as one API call per user, let's do this: https://docs.gitlab.com/ee/api/todos.html#mark-all-todos-as-done