Added Vendor Cost History on Bill and Purchase Order edit forms

Vendor Cost History was added to the Bill edit form -> Item Cost field, three dots:

  Vendor Cost History was added to the PO edit form -> Price field, three dots:

“Vendor Cost History” panel contains:

• list of POs and Bills by selected item which are grouped by Current Vendor and Other Vendors History
• data and logic should be the same as on the “Vendor Cost History” panel from Item Receipt edit form