Custom Submission Form #200

As an organiser I want to define what teams hand in, so that submissions
are comparable field by field — when judging needs a repo, a summary and a
category rather than one free-text box.

As a participant* I want to be able to submit for my team. and see how submitted what when. Submissions should be versioned and I want to be able to mark final submissions.

Done when

• The owner can create a form with questions types that include url, long text, single-choice, file-or-url.
• Submissions validate against exactly the defined questions
• Each Submission prefills the field from the previous submission with the same values but only save if any value is changed
• Organizers have access to submissions and can review them
• Existing draft/final and version behaviour is unchanged.