Use ca-cert variable for keycloak tests

[gl-johnson]

Desired Outcome

Fix pipeline failures due to OpenSSL changes.

Implemented Changes

Use updated authn-oidc configurability to provide the CA cert via Conjur policy

NOTE: this update is not required for this flow to work. The new ca-cert variable does not break the previous strategy. The reason these tests failed was a faulty openssl command:

- openssl x509 -hash -in /etc/ssl/certs/keycloak.pem -out /dev/null
+ openssl x509 -hash -in /etc/ssl/certs/keycloak.pem --noout

Additional changes:

• Fix docker compose external network deprecation warnings

NOTE: Kong examples are still failing due to changes with the Inso CLI that will be resolved in a separate effort.

Definition of Done

At least 1 todo must be completed in the sections below for the PR to be merged.

Changelog

• [ ] The CHANGELOG has been updated, or
• [x] This PR does not include user-facing changes and doesn't require a CHANGELOG update

Test coverage

• [ ] This PR includes new unit and integration tests to go with the code changes, or
• [x] The changes in this PR do not require tests

Documentation

• [ ] Docs (e.g. READMEs) were updated in this PR
• [ ] A follow-up issue to update official docs has been filed here: [insert issue ID]
• [x] This PR does not require updating any documentation

Behavior

• [ ] This PR changes product behavior and has been reviewed by a PO, or
• [ ] These changes are part of a larger initiative that will be reviewed later, or
• [x] No behavior was changed with this PR

Security

• [ ] Security architect has reviewed the changes in this PR,
• [ ] These changes are part of a larger initiative with a separate security review, or
• [x] There are no security aspects to these changes