Registration edge-cases

[Lordfirespeed]

• In case we don't give out our full ticket capacity, applications need to automatically close (perhaps certain parts of application should also 'lock' themselves) around a week or so before DurHack happens, as this is when we supply applicant data to MLH - we can't have new applicants after this point
• It might be worth adding an openApplicationsAt timestamp to the config to make doubly sure applications are not opened early via the API