Application Credential support

[Deydra71]

Jira: OSPRH-20522

Adds the end-to-end support for consuming Keystone ApplicationCredentials (AC) in the Octavia operator, enabling Octavia API, Housekeeping, Workers and Healthmanager pods to use AC-based authentication when available.

Reconcile:

On each reconcile, the Octavia API and Amphora controllers check for an AC Secret (ac-{service}-secret) using the GetApplicationCredentialFromSecret() helper from keystone-operator API:

• If the secret is missing or incomplete, continues using password authentication
• Once the AC Secret is ready with valid AC_ID and AC_SECRET fields, templates AC credentials into Octavia service configuration
• Computes hash of Secret contents and stores in configVars to trigger rolling updates when credentials rotate

Depends-On: openstack-k8s-operators/keystone-operator#567

[openshift-ci]

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