LP#1379815 Add code to assign stat cats on Vandelay imported items

LP#1379815 Add code to assign stat cats on Vandelay imported items

This commit adds columns to the Holdings Import Profile table
(vandelay.import_item_attr_definition) and to vandelay.import_item, adds
the corresponding fields to the IDL, modifies the database functions
which import the data (ingest_bib_items() and ingest_items()) and adds
code that parses the imported stat cat data (of the form
CAT 1|VALUE 1||CAT 2|VALUE 2) and applies it to the appropriate
overlayed copy.

Signed-off-by: Remington Steed <rjs7@calvin.edu>
Signed-off-by: Dan Wells <dbw2@calvin.edu>
Signed-off-by: Ben Shum <bshum@biblio.org>