ENH add a button to restart a failed submission

[tomMoral]

On the server, some submission fails for the wrong reason (issue in the dispatcher, timeout in AWS workers, missing library).
We can restart them directly on the server but this is not really a good solution (we should reduce the amount of time we ssh the server ).
What we could do it add a button in the admin dashboard, for failed submission to reset there state to new so they can be retrained.

[rth]

yes, this would be very useful and shouldn't take too much work.