ENH: Delay between check-out and check-in

[BobGlicksman]

A visitor should not be able to check-in to Maker Nexus if they checked-out within the last 5 minutes or so; at least not by scanning their badge QR code. Without such a delay, it is possible for a visitor who checks out using their badge QR code to accidently check back in. It is possible that a visitor who checks out will intentionally want to check back in -- e.g. if they realize that they left something behind in the facility, or if someone tells them about something interesting that they missed just as they were leaving. A provision should be make to allow the visitor to check back in within the lockout period; e.g. by filling out the form or having the MOD take some action on the visitor's behalf.