Backend: Need to add support for latitude and longitude into backend calls

When we submit a new (or edit an existing) coop, using this form

http://localhost:3001/directory-additions-updates

We need to add backend support for capturing the latitude and longitude (fields that will be added to this form, see here. This will primarily involve updating the serializers (specifically the CoopSerializer) here

web/directory/serializers.py

to add support for the fields latitude and longitude, part the Address model.

chicommons / maps

Backend: Need to add support for latitude and longitude into backend calls #197