psycopg2 is in maintenance mode and psycopg 3.x does not support ±infinity

[hmpf]

NAV uses ±infinity for several datetime fields. It makes for elegant comparisons and is indexable.

Sooner or later we will have to switch away from psycopg2 to psycopg 3.x, it might be as early as for Python 3.13/Django 5.1 (Uninett/Argus#942). As of today, psycopg 3.x does NOT support ±infinity.

We could write our own database backend that uses psycopg 3.x and psycopg-infdate or we could wait and hope that psycopg 3.x adds support.

Currently, testing on psycopg 3.x should yield django.db.utils.DataError: timestamp too large (after year 10K): 'infinity'.