Listing to json conversion

I think this is ready to go now.
 - agreed with Tony R which security questions need to be converted to 'choose as many as apply' fields instead of 'choose one'
 - Dates now in standard format for validation at the API
 - Updated version number for post-switch-off releases
I think `supplierId` should be a string. It happens to always be a string of digits but it's a string in the database.