Deletion of goods should be supplier specific

[jialegitgud]

Current deletion logic allows deletion via goods name. Hence, if Bread has been supplied by two suppliers, deletegoods gn/Bread will result in both suppliers records being deleted. As such, delete goods should consider both goods name and supplier name to ensure data integrity.

[yanhwee]

I suppose I can work on this. Proposed solution is to not use preamble and use two prefix arguments, of PREFIX_NAME and PREFIX_GOODS_NAME.