Updated Item table FK and Index names to be more consistent.
Updated Item table FK and Index names to be more consistent.

k-joseph/openmrs-module-openhmis.cashier,k-joseph/openmrs-module-openhmis.cashier,andrewmoko/openmrs-module-openhmis.cashier,andrewmoko/openmrs-module-openhmis.cashier,andrewmoko/openmrs-module-openhmis.cashier,k-joseph/openmrs-module-openhmis.cashier