Fixes for postgresql in u24.04

[vjrj]

Part of #834.

This uses the 24.04 variables and skip to install the pip3 psycopg2 package as is installed with apt.

TASK [postgresql : Gather OS Specific Variables] *******************************
ok: [ala-install-test-2] => (item=/data-additional/jenkins/ala-install-test/ala-install/ansible/roles/postgresql/vars/../vars/Ubuntu-24.04.yml)
(...)
TASK [postgresql : install psycopg2] *******************************************
ok: [ala-install-test-2]
(...)
TASK [postgresql : pip3 psycopg2] **********************************************
skipping: [ala-install-test-2]