Quantity-less items and request notes

[evan10s]

There are some items like sensor kits where the items are too small to track individually. In these cases it would be nice if we could mark an item as not having quantity tracked and if requests for these items included a Notes field where participants could list exactly what they want from the kit.

A workaround for this currently would be to set quantity in stock very high for the item and ask people on slack or in person what they want from the kit, but it'd be nice if we could skip the Time-intensive quantity remaining calculations for these items.