Upgrade staging database to PostgreSQL 12

This is a pre-requisite to upgrading production to version 12 as we need to shake down the post-upgrade processing and a possible means to automate such a process.

We will have to coordinate this action with SRE as this would require a pod running during the upgrade processing that will continually probe the database for the proper conditions to execute the post-upgrade tasks.

This script will probe for:

1. Database availability
2. Database version

This script work has been done on COST-379

This ticket was created to track the actual staging upgrade work.