[WIP] ci-operator: Implement 3-level naming hierarchy changes to CSI mechanism

[psalajova]

This PR implements support for the 3-level GSM secret naming structure (collection__group__field) in ci-operator, as per the design document.

Changes

3-level hierarchy

Secrets now use collection__group__field naming instead of collection__name: Before:

credentials:
  - name: aws-creds
    collection: test-platform-infra
    mount_path: /tmp/aws

After:

credentials:
  - collection: test-platform-infra
    group: cluster-init
    field: aws-creds
    mount_path: /tmp/aws

Supported credential resolution modes

There are three ways one can reference credentials:

1. Bundle reference (via gsm-config.yaml):

credentials:
  - bundle: aws-bundle
    mount_path: /tmp/aws

2. Auto-discovery (lists all fields for collection+group):

credentials:
  - collection: test-platform-infra
    group: cluster-init
    mount_path: /tmp/secrets

4. Explicit field:

credentials:
  - collection: test-platform-infra
    group: cluster-init
    field: aws-creds
    mount_path: /tmp/aws

Implementation details

• Wired gsmConfig through main.go → defaults → multi_stage chain
• Credentials are resolved once during createSPCs() before SecretProviderClass creation
• Added validation to prevent file collisions when different groups share the same mount path
• Censoring SPCs now track credentials by full secret name (collection__group__field)
• Updated all tests to use 3-level structure
• A separate PR needs to be done which will make sure ci-operator has gsm-config.yaml available at all times, as this is critical for bundle resolution.

Jira: https://issues.redhat.com/browse/DPTP-4656