Pimpy clickable 'groups without tasks' buttons.
Groups that do not contain any assigned tasks for users are now also clickable.
These groups will automatically link to /pimpy/minutes?group=<groupId>
even if they're on /pimpy/tasks
, because it doesn't really make sense for the user to stay on .../tasks
if there are no tasks in the group.
Closes #1250 (closed)