Deprecate Azure v1 Storage Driver for Container Registry
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## Summary
The legacy Azure storage driver for GitLab Container Registry will be deprecated in GitLab 18.0 and removed in GitLab 19.0.
## Motivation
The legacy driver uses older Azure SDK components with limitations in functionality and performance. The new Azure v2 driver provides improved reliability, better performance, and a more maintainable codebase.
## Proposal
1. Add deprecation notices to:
* GitLab deprecation documentation (https://docs.gitlab.com/ee/update/deprecations.html)
* Admin configuration documentation (https://docs.gitlab.com/ee/administration/packages/container_registry.html)
* Release notes for GitLab 18.0
2. Implement runtime log warnings when users are running the deprecated Azure v1 driver:
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`WARNING: You are using the deprecated Azure v1 storage driver.
Please migrate to the v2 driver before GitLab 19.0.`
3. Ensure clear migration instructions are available for users to switch from v1 to v2
4. Coordinate customer outreach to find users willing to test the Azure v2 driver
## Rollout Plan
* GitLab 18.0 (Feb/March 2025): Deprecation announced, Azure v2 available as beta
* GitLab 18.3 (May 2025): Continue Azure v2 beta with improvements based on user feedback
* GitLab 19.0: Azure v2 becomes GA, Azure v1 driver removed completely
## Documentation
Documentation should include:
* Announcement of the deprecation timeline
* Migration instructions
* Reference to detailed Azure v2 documentation (https://gitlab.com/gitlab-org/container-registry/-/blob/master/docs/storage-drivers/azure_v2.md)
* Testing recommendations
* Authentication configuration changes
issue