5306 Track POS Items Better

User Story:
As an admin at RaceEntry, I need to be sure that I've got every POS device accounted for before I ship them out to the event. As such, I would like to be unable to print the shipping label for the order until every device in the order has been scanned out.

Also as an admin at RaceEntry, sometimes I need to ship a replacement device to an event. Currently when this happens, it is done outside of the system. I need the system to allow me to send replacement devices to an event with a current order so that the system knows that such-and-such device was sent to so-and-so's event as a replacement device.

Definition of done:
On the POS order modal, if not all of the devices have been scanned out, the print shipping label button does not appear. Instead there is a message reminding the user that all devices need to be scanned out before the label can be printed.

On the POS order modal, if the order's devices are still at the event and not late, an admin will see a button for "Send Replacement Devices". Clicking this takes the admin to a page which is very similar to the POS rental page. The admin fills out the order and "checks out" (the event director will not pay for this order). This creates a new POS order of a new type ("Replacement Order" until Hyrum tells me otherwise).

These Replacement Orders show up in the POS orders table. They reference the original order. The event director will get an email when said order ships to them.

Replacement orders will NOT get charged late fees, per Hyrum's instructions.