Create a common DB Writer class to be used by many scripts

[rudokemper]

Feature Request

Right now, comapeo_observations, odk_responses, kobo_responses, locusmap, and alerts_gcs have a DBWriter class to manage converting a dataset into structured SQL tables and writing them to Postgres using psycopg2.

There is a tremendous amount of duplication of code across these classes; for all but the alerts script, there is little to no difference whatsoever, sans minor differences in logging messages or some specific property like the exact name of the primary key field.

Let's come up with a common DB Writer class that all of these scripts can use as a modular import, stored in f/common_logic.

In so doing, we can upgrade to psycopg3.