View for "Users With Active Tasks"

[philippotto]

Build a front-end view for api/projects/<name>/usersWithOpenTasks which is available from the projects view.

• add a button to the projects view
• show a modal that displays all users with active tasks of the selected project
• add a button next to each user that if clicked, transfers all its tasks to a selected user

https://discuss.webknossos.org/t/show-active-users/561

[philippotto]

I think this would be a nice task for @MichaelBuessemeyer. When you are done with your other tasks, you can hit up @daniel-wer or me to talk over this 😎