ensure primary key values all present for ORM bulk UPDATE

ensure primary key values all present for ORM bulk UPDATE

Fixed bug in new feature where ORM bulk UPDATE can be combined with a WHERE
clause, added in version 2.0.11 as part of :ticket:`9583`, where sending
dictionaries that did not include the primary key values for each row would
run through the bulk process and include "pk=NULL" for the rows, silently
failing.   An exception is now raised if primary key values for bulk UPDATE
are not supplied.

Additionally, document WHERE criteria feature as well as how to
invoke an UPDATE outside of "bulk orm by primary key"

Fixes: #9917
Change-Id: Ie8e0d604050f0dfbab77473020771383c087d14a