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
• 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
• 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]
• 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
• 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
• There are no security aspects to these changes