Add missing fields to acq-models

There appear to be several fields missing from the schemas that appear in the orders mock-ups. These need to be identified and acq-models needs to be updated.

So far I've identified the following as missing:

• publisher (po_line)
• publication_date (details)
• product_id_type - e.g. ISBN/ISSN/etc. (details)
• contributor (po_line)
• contributor_type (po_line)
• title (move to po_line)
• tags (po_line)
• vendor (purchase_order) - e.g. UUID pointing to Vendor record
• quantity - electronic and physical properties ("quantity" is only in the location schema now)
• approval_status (purchase_order) This appears to be part of the workflow status (see details UXPROD-767).
• fund_code (po_line): there is a fund_distribution schema, but it is only tied to a PO line via the fund_distribution schema, not the po_line schema.
• manual_po (purchase_order)
• po_line_payment_status (po_line): there is a payment status in the po, but not po_line. The entity diagram mentions po_line_payment_status.
• order_type (see details UXPROD-770) - collapse to a single enum field in PurchaseOrder
• order_format (see details UXPROD-768) - Collapse to single enum field in PurchaseOrderLine
• workflow_status/po_line_workflow_status - make enums
• aquisitiion_method - make enum
• rush (po_line) - boolean
• payment_status (po_line) - enum
• receipt_status (po_line) - enum
• material_type -> allow multiple
• product_id -> allow multiple
• remove unused schemas