Workflow dashboard improvement when user is admin

Currently when user is admin, he sees all tasks, since query is based on acls. That's a good behavior for all other users, as it is probably the most efficient, so we should keep it. But when user is part of administrators group, consequence is that it is difficult for him to find its tasks.
administrators users should have two tabs: the first one, My tasks, that uses the queries based on filtering on the actors and deleguatee fields, and a second one : "Tasks administration", that uses the query based on filters.