Describe the change
In response to #506, this PR updates the associated Postgres version to run the newest available release, which is postgres 15.14. Additionally, updated the generic testing DB variables to reflect the new syntax in the newer version.

Describe testing procedures
Tested with local build of the application and ensured that scans still worked properly with the UI.

Sample output
N/A

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of and tested my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings