Configure Geo for Staging Ref environment

Geo setup is mentioned in the next iteration in New Staging epic. This issue is to discuss this requirement and plan the work if needed.

High-level steps

• ✅ 1. Discuss Geo set up - current issue, #350741 (comment 817084975)
• 2. Configure Geo on Staging Ref - #350869 (closed)
• ✅ 3. Configure QA pipelines - #350870 (closed)

Staging Ref

Infrastructure and Quality teams are working a new staging environment called Staging Ref where engineers will have full access to Gitlab environment and will be able to test their features without restrictions that they have on the current Staging.

Detailed Staging Ref information.

Staging Ref will be 10k hybrid environment (GCP) and can be destroyed/rebuilt if needed. Please see &6401 (closed)

                -> staging-ref (new) -> QA      
              /                                         
gstg-migrations -> gstg-cny (new) -> QA (new) -> gstg -> QA -> gprd-migrations -> gprd-cny -> QA -> gprd 

Staging Ref is deployed with GitLab Environment Toolkit and Deployer.

If Staging Ref is rebuilt, it should be reseeded with all required test data.

Full documentation: https://about.gitlab.com/handbook/engineering/infrastructure/environments/staging-ref/