How to categorize this issue?

/area usability
/kind enhancement

What would you like to be added:
In order to introduce NamespacedCloudProfiles (see GEP-25) the following tasks need to be done:

• Gardener Enhancement Proposal [GEP-25] Namespaced Cloud Profiles #9142
• API Changes [GEP-25] Add NamespacedCloudProfile API and validations #9440
• Adjust admission controller of known providers (after vendored to API adjustments)
  • Alicloud: part of Enable support for NamespacedCloudProfiles, including custom machine images (versions) gardener-extension-provider-alicloud#755
  • AWS: [GEP-25] Enable Shoot cloudProfile reference as complement to cloudProfileName gardener-extension-provider-aws#1000
  • Azure: [GEP-25] Enable Shoot cloudProfile reference as complement to cloudProfileName gardener-extension-provider-azure#922
  • GCP: [GEP-25] Enable Shoot cloudProfile reference as complement to cloudProfileName gardener-extension-provider-gcp#853
  • OpenStack: [GEP-25] Enable Shoot cloudProfile reference as complement to cloudProfileName gardener-extension-provider-openstack#834
  • Ironcore: [GEP-25] Enable Shoot cloudProfile reference as complement to cloudProfileName ironcore-dev/gardener-extension-provider-ironcore#636
• Gardener adjustments
  • Default shoot.spec.cloudProfile.kind to CloudProfile: Enable cloudProfile reference as complement to cloudProfileName #10093
  • Adjust admission plugins
  • Adjust SeedAuthorizer: Add custom rbac verbs to allow modification of NamespacedCloudProfile.Spec.{Kubernetes,MachineImages} #10485
  • Adjust Cluster resource handling
  • Add NamespacedCloudProfile controller: Implement NamespacedCloudProfile controller #10266
• Migrate shoot.spec.cloudProfileName to cloudProfile field if feature is enabled
  • Transfer field information
  • Automatically set shoot.spec.cloudProfile when shoot.spec.cloudProfileName is configured
  • With Enable cloudProfile reference as complement to cloudProfileName #10093 shoot.spec.cloudProfileName and shoot.spec.cloudProfile are synced in both directions
• Further dependencies and usages to keep an eye on
  • Make gardenctl aware of NamespacedCloudProfiles: Support Namespaced Cloud Profiles gardenctl-v2#462
  • Inventory project
• Graduate feature gate to beta: Graduate feature gate UseNamespacedCloudProfile to Beta #11289
• Graduate feature gate to GA: Graduate UseNamespacedCloudProfile feature gate to GA #12620
• Remove feature gate with Gardener v1.128
• Deprecate shoot.spec.cloudProfileName field: Proceed with replacement of Shoot .spec.cloudProfileName field in favor of shoot.spec.cloudProfile with new Kubernetes versions #11816
• Revisit future enhancements, e.g. support "custom" os images for projects (cc @marwinski @dguendisch).
  • Fix manual status updates: Use NamespacedCloudProfile status handler properly #10937
    • g/g: Use Subresource to mutate NamespacedCloudProfile status #11036
    • AWS: Use Subresource to mutate NamespacedCloudProfile status gardener-extension-provider-aws#1169
    • Azure: Use Subresource to mutate NamespacedCloudProfile status gardener-extension-provider-azure#1039
    • GCP: Use Subresource to mutate NamespacedCloudProfile status gardener-extension-provider-gcp#942
    • Openstack: Use Subresource to mutate NamespacedCloudProfile status gardener-extension-provider-openstack#930
    • Alicloud: part of Enable support for NamespacedCloudProfiles, including custom machine images (versions) gardener-extension-provider-alicloud#755
  • Make use of SingleObjectCache: Use SingleObjectCache for NamespacedCloudProfiles #11014 (cleanup prior implementation).
  • Support custom machine images and versions: Allow custom machine images and versions in NamespacedCloudProfiles #10629
    • adjust known provider-extensions (after vendoring to g/g version v1.108.0)
      • Alicloud: part of Enable support for NamespacedCloudProfiles, including custom machine images (versions) gardener-extension-provider-alicloud#755
      • AWS: Add NamespacedCloudProfile validation and mutation webhooks gardener-extension-provider-aws#1136
      • Azure: Add NamespacedCloudProfile validation and mutation webhooks gardener-extension-provider-azure#1016
        • Fix validation regarding architectures: Validate NamespacedCloudProfile MachineImage architectures against providerConfig gardener-extension-provider-azure#1021
      • GCP: Add NamespacedCloudProfile validation and mutation webhooks gardener-extension-provider-gcp#918
      • OpenStack: Add NamespacedCloudProfile validation and mutation webhooks gardener-extension-provider-openstack#911
  • Allow switching (back) from a NamespacedCloudProfile to its parent CloudProfile: Support switching cloud profile referenced in Shoot from NamespacedCloudProfile to parent CloudProfile. #10811
  • Fix status calculation for custom images (versions) being added to the CloudProfile after initial definition in the NamespacedCloudProfile: Fix NamespacedCloudProfile validation for {MachineImages,MachineTypes} added to parent CloudProfile later #11093

Future work / tracked separately:

• Implement necessary changes in dashboard: Support shoot.Spec.CloudProfile with CloudProfiles and NamespacedCloudProfiles besides CloudProfileName dashboard#1971