Deletion in Cascade

Delete an election should delete areas which should delete sections, which should delete desks.

changed milestone to %Generic election

added Backend To Do bug labels

changed due date to May 19, 2020

added Doing label and removed To Do label

created branch 18-deletion-in-cascade to address this issue

mentioned in merge request !12 (merged)

closed via merge request !12 (merged)

mentioned in commit d5118d36