Add "received by" metadata for inventory items inside objects/attachments.
Create llGetInventoryGiver() function to read giver key.
Giver key is known by the server when the viewer sends ImprovedInstantMessage.
Giver key is known by the server with every use of llGiveInventory().
Inventory prior to code implementation returns NULL_KEY.
A viewer UI element for the Item Properties floater is not needed at this time.