Add photo upload stage
See RT 230380 https://tickets.ch.cam.ac.uk/rt/Ticket/Display.html?id=230380
We want it to be compulsory for a photo of a person to have been uploaded before they can be registered. The photos will be uploaded by Photography. The starters will be told to go and make an appointment with Photography.
Getting their photo sorted can happen any time after the personal details form is submitted - before that Photography might not be able to determine the appropriate registration form to connect the photo to as there may be no identifying data there. It can happen in parallel with all the safety-related tasks though.
Because the starter may not have a person record already we should upload the photo to the registration form record, and have the importer function apply it to the person record when the registration form is imported. This means it would be very advantageous to resolve admin-database-schema#12 (closed) first, as then we can store images in the modern way.