Create "Extend" button for batches on dashboard page

[robert-w-gries]

Gina mentioned there can be a lot of batches, so deleting early before the 48 hours will help clean up the dashboard page

Jessica would like to extend certain batches because she sometimes can't get to them in time if she emailed a bunch to herself at once from the court.

Additionally, investigate the ability to auto-extend the deletion date whenever the batch is updated.