Upgrade Silverstripe CMS to psycopg3

[Kyle-Neale]

What does this PR do?

Motivation

Review checklist (to be filled by reviewers)

• Feature or bugfix MUST have appropriate tests (unit, integration, e2e)
• Add the qa/skip-qa label if the PR doesn't need to be tested during QA.
• If you need to backport this PR to another branch, you can add the backport/<branch-name> label to the PR and it will automatically open a backport PR once this one is merged

[codecov]

Codecov Report

Attention: Patch coverage is 30.00000% with 7 lines in your changes missing coverage. Please review.

Project coverage is 90.46%. Comparing base (812031e) to head (d95ae31).

Additional details and impacted files

Flag	Coverage Δ
activemq	?
cassandra	?
confluent_platform	?
hive	?
hivemq	?
hudi	?
ignite	?
jboss_wildfly	?
kafka	?
presto	?
silverstripe_cms	75.63% <30.00%> (-0.37%)	⬇️
solr	?
tomcat	?
weblogic	?

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