Onboarding tasks: give possibility to performers to reopen tasks

Summary:

For us, it would be very useful if performers of the Preboarding and Onbaording tasks could re-open the tasks themselves, and it would not be necessary for the task owner or an administrator to intervene and re-open the task to the candidate.

Content (required):

The candidate sometimes mistakes loading documents into a task and clicks 'done'. Subsequently, the candidate can no longer reload the correct document version until the task owner or system administrator intervenes and reopens the task. It could be very useful and timesaving if the candidate could reopen the task by himself and so reload the correct version of the documents. In fact, this would avoid the candidate having to write e-mails requesting the reopening of the task and the effort on the part of the task owner to reopen the task.