Add individual shelves

[MaddyPhi]

The individual shelves would allow the user to be able to add individual shelves (as many or as few as they desire to

• create a single rack
• create a localized trigger system for loading shelves that allows searching for nearby racks to load
• create a localized trigger system to unload shelves to that allows the rack to search for nearby unload triggers

Depends on #5
Depends on #11