#60124054 Make questions/dividers sortable on new survey page, update position inputs after sort
#60124054 Use CSS to display:none delete for first question on new survey page.
This is robust to reordering of the questions, unlike previous approach.
Bug fix: Adding a multiple choice question answer was broken by 854ccbe0227427b3992a531ec1058a8c5a73cee6.
More complex form structure means its safer to split up adding a question/divider, and adding an answer.