Add button to delete content on edition
custom_forms: use rails nested forms in form partial

AI2780
Export CSV
Fixes crash with submissions without profile
Validates there is at least one alternative
Fixes Cancel button
Expired forms can't be answered
change message for error in select field without alternatives
Makes it possible to order fields by dragdrop
removes trailing whitespaces
Changes date format in csv
User can order submissions in alphabetical order
Adds functional test for exporting as csv
Adds form required for community admission
Adds named_scope for easy retrieval of tasks requested by profile
Cancels survey tasks after removing a form
Makes it possible for the admin to see pending submissions
Changes button order so remove button is last
Changes string from default value to default text
Fixes unit test name for admission survey