chore: replace decommissioned giantswarmpublic.azurecr.io registry

[marians]

What

The giantswarmpublic.azurecr.io registry, which hosted Giant Swarm Helm chart catalogs, has been decommissioned. All chart catalogs are now consolidated onto oci://gsoci.azurecr.io/charts/giantswarm/.

This PR replaces all references accordingly:

• oci://giantswarmpublic.azurecr.io/giantswarm-catalog/ → oci://gsoci.azurecr.io/charts/giantswarm/
• giantswarmpublic.azurecr.io/giantswarm-catalog/hello-world-app → gsoci.azurecr.io/charts/giantswarm/hello-world (the demo app's chart is named hello-world on the new registry; the path also changes, not just the domain)
• Bare giantswarmpublic.azurecr.io/giantswarm-catalog (e.g. prose in docs) → gsoci.azurecr.io/charts/giantswarm

Files changed

• docs/add_wc_environments.md
• bases/environments/stages/{dev,staging}/hello_app_cluster/imagerepositories.yaml
• bases/environments/stages/{dev,staging}/hello_app_cluster/automatic_updates/catalog.yaml
• management-clusters/MC_NAME/organizations/ORG_NAME/workload-clusters/WC_NAME_OUT_OF_BAND_{FLUX,NO_FLUX}_APP/mapi/apps/hello-world-automatic-updates/imagerepository.yaml
• management-clusters/MC_NAME/organizations/ORG_NAME/workload-clusters/WC_NAME_OUT_OF_BAND_{FLUX,NO_FLUX}_APP/mapi/automatic-updates/catalog.yaml
• tests/ats/assertions/exists/organizations/workload-clusters/hello-app-{dev,staging}-1/catalogs.yaml
• tests/ats/assertions/exists/organizations/workload-clusters/hello-app-{dev,staging}-1/imagerepositories.yaml

Intentionally left untouched: simple-db-app

The simple-db-app chart no longer exists and is not available on gsoci. All lines referencing simple-db-app are deliberately left pointing at the old giantswarmpublic.azurecr.io registry and are not modified in this PR. Replacing the simple-db-app demo is tracked separately in #131.

[github-actions]

Validation output log

yamllint: OK
kubeconform: OK

yamllint: OK
kubeconform: OK

yamllint: OK
kubeconform: OK

yamllint: OK
kubeconform: OK

yamllint: OK
kubeconform: OK

yamllint: OK
kubeconform: OK

yamllint: OK
kubeconform: OK

yamllint: OK
kubeconform: OK

yamllint: OK
kubeconform: OK

[github-actions]

Rendered manifest diff output log

/spec/repositories/0/URL  (Catalog/org-org-name/giantswarm-catalog-oci)
  ± value change
    - oci://giantswarmpublic.azurecr.io/giantswarm-catalog/
    + oci://gsoci.azurecr.io/charts/giantswarm/

/spec/storage/URL  (Catalog/org-org-name/giantswarm-catalog-oci)
  ± value change
    - oci://giantswarmpublic.azurecr.io/giantswarm-catalog/
    + oci://gsoci.azurecr.io/charts/giantswarm/

/spec/image  (ImageRepository/org-org-name/hello-app-staging-1-hello-app)
  ± value change
    - giantswarmpublic.azurecr.io/giantswarm-catalog/hello-world-app
    + gsoci.azurecr.io/charts/giantswarm/hello-world

/spec/image  (ImageRepository/org-org-name/mapi-out-of-band-flux-app-hello-world)
  ± value change
    - giantswarmpublic.azurecr.io/giantswarm-catalog/hello-world-app
    + gsoci.azurecr.io/charts/giantswarm/hello-world

/spec/storage/URL  (Catalog/giantswarm/giantswarm-catalog-oci)
  ± value change
    - oci://giantswarmpublic.azurecr.io/giantswarm-catalog/
    + oci://gsoci.azurecr.io/charts/giantswarm/

/spec/image  (ImageRepository/org-org-name/mapi-out-of-band-no-flux-hello-world)
  ± value change
    - giantswarmpublic.azurecr.io/giantswarm-catalog/hello-world-app
    + gsoci.azurecr.io/charts/giantswarm/hello-world

/spec/storage/URL  (Catalog/giantswarm/giantswarm-catalog-oci)
  ± value change
    - oci://giantswarmpublic.azurecr.io/giantswarm-catalog/
    + oci://gsoci.azurecr.io/charts/giantswarm/

/spec/repositories/0/URL  (Catalog/org-org-name/giantswarm-catalog-oci)
  ± value change
    - oci://giantswarmpublic.azurecr.io/giantswarm-catalog/
    + oci://gsoci.azurecr.io/charts/giantswarm/

/spec/storage/URL  (Catalog/org-org-name/giantswarm-catalog-oci)
  ± value change
    - oci://giantswarmpublic.azurecr.io/giantswarm-catalog/
    + oci://gsoci.azurecr.io/charts/giantswarm/

/spec/image  (ImageRepository/org-org-name/hello-app-dev-1-hello-app)
  ± value change
    - giantswarmpublic.azurecr.io/giantswarm-catalog/hello-world-app
    + gsoci.azurecr.io/charts/giantswarm/hello-world