Util functions add, remove, search, and get inventory complete

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add, remove, search, and get inventory routing are completed.

1.) Add will send back an object with the id, name, and distance of the item for front end to use.
2.) Remove will just remove the item without sending anything back (should we send something back?)
3.) Search is already handled
4.) getInventory will return an object for each item with its id, name, and distance.

----------------------DO NOT MERGE----------------------