Feature flag: FF_ENABLE_DOMAIN_REDIRECT

Summary

This issue is to rollout Add support for domain level redirects on production, that is currently behind the FF_ENABLE_DOMAIN_REDIRECT feature flag.

Expectations

What are we expecting to happen?

User will be able to add domain level redirects in pages.

What might happen if this goes wrong?

In pages, domain level redirects will be affected. In that case, we can revert this MR: !936 (merged)

Rollout Steps

• Temporarily enable with environment variable: gitlab-com/gl-infra/k8s-workloads/gitlab-com!3395 (merged)
• Enable by default (optional): !960 (merged)
• Remove the feature flag: Link to the MR

Rollback Considerations/Events

• Disabling with environment variable: Link to the MR
• Remove the feature flag: Remove feature flag: FF_ENABLE_DOMAIN_REDIRECT (#1097 - closed)