LP#1942220: various updates to business logic

LP#1942220: various updates to business logic

* set 024 ind1 correctly (i.e., to '1') when applying UPC as order
  identifier

* add flesh_po_items_further option to PO retrieval

  This fleshes in any fund debits and debit invoice items associated
  with PO direct charges

* add open-ils.acq.po_item.disencumber method

  This method disencumbers a PO item by setting its fund debit's amount
  to zero. Note that this can be done only for encumbrances; if the
  debit is an expenditure, it cannot be changed.

* add flesh_li_details_receiver to LI retrieval

* add two additional fleshing options to LI retrieval

  Specifically, flesh_copy_location and flesh_call_number. These take
  effect only when flesh_copies is also true and are used to further
  flesh values of items attached to line item details.

* remove cancel reason if last LID of LI is received

  Otherwise, a sequence where a line item was cancelled but one of
  its items was received would have the LI end up in a received
  state but with a cancel reason.

Signed-off-by: Galen Charlton <gmc@equinoxOLI.org>