target specific field when updating collections

[EricOuma]

PROBLEM
collection.update() creates the whole data dictionary for objects even for field that have not changed. This is time and resource intensive e.g when only one field has been updated

SOLUTION
Allow specification of the fields to be updated. Should have the same API as https://docs.djangoproject.com/en/4.2/ref/models/instances/#specifying-which-fields-to-save