Remove "Remove location marker" from the item data card

[cynthiamah]

To do item from wrap up meeting 8/20/18

Remove "Remove location marker" button from the item data card

Reasoning:
This command should rarely (if ever) be used. It is currently in a very prominent place on the item data card. The user can still remove the marker for an item (but keep it's data record), in the data table view.

[vanwars]

Agreed. If there's no marker, there should be an add marker. But if they want to remove the marker, they can do it in the spreadsheet.